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Handbook of biodegradable Polymers
Edited by Andreas Lendlein and Adam Sisson Handbook of Biodegradable Polymers Further Reading Loos, K (Ed.) Biocatalysis in Polymer Chemistry 2011 Hardcover ISBN: 978-3-527-32618-1 Matyjaszewski, K., Müller, A H E (Eds.) Controlled and Living Polymerizations From Mechanisms to Applications 2009 ISBN: 978-3-527-32492-7 Mathers, R T., Maier, M A R (Eds.) Green Polymerization Methods Renewable Starting Materials, Catalysis and Waste Reduction 2011 Hardcover ISBN: 978-3-527-32625-9 Matyjaszewski, K., Gnanou, Y., Leibler, L (Eds.) Macromolecular Engineering Precise Synthesis, Materials Properties, Applications 2007 Hardcover ISBN: 978-3-527-31446-1 Yu, L Biodegradable Polymer Blends and Composites from Renewable Resources Fessner, W.-D., Anthonsen, T (Eds.) Modern Biocatalysis Stereoselective and Environmentally Friendly Reactions 2009 Hardcover ISBN: 978-0-470-14683-5 2009 ISBN: 978-3-527-32071-4 Elias, H.-G Janssen, L., Moscicki, L (Eds.) Macromolecules Thermoplastic Starch 2009 Hardcover ISBN: 978-3-527-31171-2 A Green Material for Various Industries 2009 Hardcover ISBN: 978-3-527-32528-3 Edited by Andreas Lendlein and Adam Sisson Handbook of Biodegradable Polymers Synthesis, Characterization and Applications The Editors Prof Andreas Lendlein GKSS Forschungszentrum Inst für Chemie Kantstr 55 14513 Teltow Germany All books published by Wiley-VCH are carefully produced Nevertheless, authors, editors, and publisher not warrant the information contained in these books, including this book, to be free of errors Readers are advised to keep in mind that statements, data, illustrations, procedural details or other items may inadvertently be inaccurate Library of Congress Card No.: applied for Dr Adam Sisson GKSS Forschungszentrum Zentrum f Biomaterialentw Kantstraße 55 14513 Teltow Germany British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library Bibliographic information published by the Deutsche Nationalbibliothek The Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at < http://dnb.d-nb.de> © 2011 Wiley-VCH Verlag & Co KGaA, Boschstr 12, 69469 Weinheim, Germany All rights reserved (including those of translation into other languages) No part of this book may be reproduced in any form – by photoprinting, microfilm, or any other means – nor transmitted or translated into a machine language without written permission from the publishers Registered names, trademarks, etc used in this book, even when not specifically marked as such, are not to be considered unprotected by law Cover Design Grafik-Design Schulz, Fgưnheim Typesetting Toppan Best-set Premedia Limited, Hong Kong Printing and Binding Fabulous Printers Pte Ltd, Singapore Printed in Singapore Printed on acid-free paper ISBN: 978-3-527-32441-5 ePDF ISBN: 978-3-527-63583-2 ePub ISBN: 978-3-527-63582-5 Mobi ISBN: 978-3-527-63584-9 oBook ISBN: 978-3-527-63581-8 V Contents Preface XV List of Contributors XVII 1.1 1.1.1 1.1.2 1.2 1.2.1 1.2.2 1.2.3 1.3 1.3.1 1.3.2 1.3.3 1.3.4 1.4 1.4.1 1.4.2 1.5 1.5.1 1.5.2 1.5.3 2.1 2.2 2.3 2.4 Polyesters Adam L Sisson, Michael Schroeter, and Andreas Lendlein Historical Background Biomedical Applications Poly(Hydroxycarboxylic Acids) Preparative Methods Poly(Hydroxycarboxylic Acid) Syntheses Metal-Free Synthetic Processes Polyanhydrides Physical Properties Crystallinity and Thermal Transition Temperatures Improving Elasticity by Preparing Multiblock Copolymers Covalently Crosslinked Polyesters 11 Networks with Shape-Memory Capability 11 Degradation Mechanisms 12 Determining Erosion Kinetics 12 Factors Affecting Erosion Kinetics 13 Beyond Classical Poly(Hydroxycarboxylic Acids) 14 Alternate Systems 14 Complex Architectures 15 Nanofabrication 16 References 17 Biotechnologically Produced Biodegradable Polyesters 23 Jaciane Lutz Ienczak and Gláucia Maria Falcão de Aragão Introduction 23 History 24 Polyhydroxyalkanoates – Granules Morphology 26 Biosynthesis and Biodegradability of Poly(3-Hydroxybutyrate) and Other Polyhydroxyalkanoates 29 VI Contents 2.4.1 2.4.2 2.4.3 2.5 2.6 2.7 3.1 3.2 3.2.1 3.2.2 3.2.3 3.2.4 3.2.5 3.2.6 3.2.7 3.2.8 3.2.9 3.2.10 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 4.1 4.2 4.2.1 4.2.1.1 4.2.1.2 4.2.1.3 4.2.2 4.2.2.1 4.2.2.2 Polyhydroxyalkanoates Biosynthesis on Microorganisms Plants as Polyhydroxyalkanoates Producers 32 Microbial Degradation of Polyhydroxyalkanoates 33 Extraction and Recovery 34 Physical, Mechanical, and Thermal Properties of Polyhydroxyalkanoates 36 Future Directions 37 References 38 29 Polyanhydrides 45 Avi Domb, Jay Prakash Jain, and Neeraj Kumar Introduction 45 Types of Polyanhydride 46 Aromatic Polyanhydrides 46 Aliphatic–Aromatic Polyanhydrides 49 Poly(Ester-Anhydrides) and Poly(Ether-Anhydrides) 49 Fatty Acid-Based Polyanhydrides 49 RA-Based Polyanhydrides 49 Amino Acid-Based Polyanhydrides 51 Photopolymerizable Polyanhydrides 52 Salicylate-Based Polyanhydrides 53 Succinic Acid-Based Polyanhydrides 54 Blends 55 Synthesis 55 Properties 58 In Vitro Degradation and Erosion of Polyanhydrides 63 In Vivo Degradation and Elimination of Polyanhydrides 64 Toxicological Aspects of Polyanhydrides 65 Fabrication of Delivery Systems 67 Production and World Market 68 Biomedical Applications 68 References 71 Poly(Ortho Esters) 77 Jorge Heller Introduction 77 POE II 79 Polymer Synthesis 79 Rearrangement Procedure Using an Ru(PPh3)3Cl2 Na2CO3 Catalyst 80 Alternate Diketene Acetals 80 Typical Polymer Synthesis Procedure 80 Drug Delivery 81 Development of Ivermectin Containing Strands to Prevent Heartworm Infestation in Dogs 81 Experimental Procedure 81 Contents 4.2.2.3 4.3 4.3.1 4.3.1.1 4.3.1.2 4.3.1.3 4.3.2 4.4 4.4.1 4.4.2 4.4.3 4.4.4 4.4.5 4.4.5.1 4.4.5.2 4.4.6 4.4.6.1 4.4.6.2 4.4.7 4.5 4.5.1 4.5.2 4.5.3 4.5.3.1 4.5.3.2 4.5.4 4.5.4.1 4.5.4.2 4.5.5 4.5.6 4.5.6.1 4.5.6.2 4.5.6.3 4.5.6.4 4.6 4.7 Results 82 POE IV 82 Polymer Synthesis 82 Typical Polymer Synthesis Procedure 82 Latent Acid 83 Experimental Procedure 83 Mechanical Properties 83 Solid Polymers 86 Fabrication 86 Polymer Storage Stability 87 Polymer Sterilization 87 Polymer Hydrolysis 88 Drug Delivery 91 Release of Bovine Serum Albumin from Extruded Strands 91 Experimental Procedure 93 Delivery of DNA Plasmid 93 DNA Plasmid Stability 94 Microencapsulation Procedure 94 Delivery of 5-Fluorouracil 95 Gel-Like Materials 96 Polymer Molecular Weight Control 96 Polymer Stability 98 Drug Delivery 99 Development of APF 112 Mepivacaine Delivery System 99 Formulation Used 99 Preclinical Toxicology 100 Polymer Hydrolysate 100 Wound Instillation 100 Phase II Clinical Trial 100 Development of APF 530 Granisetron Delivery System 100 Preclinical Toxicology 100 Rat Study 101 Dog Study 101 Phase II and Phase III Clinical Trials 101 Polymers Based on an Alternate Diketene Acetal 102 Conclusions 104 References 104 Biodegradable Polymers Composed of Naturally Occurring α-Amino Acids 107 Ramaz Katsarava and Zaza Gomurashvili Introduction 107 Amino Acid-Based Biodegradable Polymers (AABBPs) 109 Monomers for Synthesizing AABBPs 109 Key Bis-Nucleophilic Monomers 109 Bis-Electrophiles 111 5.1 5.2 5.2.1 5.2.1.1 5.2.1.2 VII VIII Contents 5.2.2 5.2.3 5.2.3.1 5.2.3.2 5.2.3.3 5.2.3.4 5.2.4 5.2.4.1 5.2.4.2 5.2.4.3 5.2.5 5.2.6 5.3 AABBPs’ Synthesis Methods 111 AABBPs: Synthesis, Structure, and Transformations 115 Poly(ester amide)s 115 Poly(ester urethane)s 119 Poly(ester urea)s 119 Transformation of AABBPs 119 Properties of AABBPs 121 MWs, Thermal, Mechanical Properties, and Solubility 121 Biodegradation of AABBPs 121 Biocompatibility of AABBPs 123 Some Applications of AABBPs 124 AABBPs versus Biodegradable Polyesters 125 Conclusion and Perspectives 126 References 127 Biodegradable Polyurethanes and Poly(ester amide)s 133 Alfonso Rodríguez-Galán, Lourdes Franco, and Jordi Puiggalí Abbreviations 133 Chemistry and Properties of Biodegradable Polyurethanes 134 Biodegradation Mechanisms of Polyurethanes 140 Applications of Biodegradable Polyurethanes 142 Scaffolds 142 Cardiovascular Applications 143 Musculoskeletal Applications 143 Neurological Applications 144 Drug Delivery Systems 144 Other Biomedical Applications 145 New Polymerization Trends to Obtain Degradable Polyurethanes 145 Polyurethanes Obtained without Using Diisocynates 145 Enzymatic Synthesis of Polyurethanes 146 Polyurethanes from Vegetable Oils 147 Polyurethanes from Sugars 147 Aliphatic Poly(ester amide)s: A Family of Biodegradable Thermoplastics with Interest as New Biomaterials 149 Acknowledgments 152 References 152 6.1 6.2 6.3 6.3.1 6.3.1.1 6.3.1.2 6.3.1.3 6.3.2 6.3.3 6.4 6.4.1 6.4.2 6.4.3 6.4.4 6.5 7.1 7.2 7.3 7.4 7.5 7.6 Carbohydrates 155 Gerald Dräger, Andreas Krause, Lena Möller, and Severian Dumitriu Introduction 155 Alginate 156 Carrageenan 160 Cellulose and Its Derivatives 162 Microbial Cellulose 164 Chitin and Chitosan 165 Contents 7.7 7.8 7.9 7.10 7.11 7.12 7.13 7.14 Dextran 169 Gellan 171 Guar Gum 174 Hyaluronic Acid (Hyaluronan) 176 Pullulan 180 Scleroglucan 182 Xanthan 184 Summary 186 Acknowledgments 187 In Memoriam 187 References 187 Biodegradable Shape-Memory Polymers 195 Marc Behl, Jörg Zotzmann, Michael Schroeter, and Andreas Lendlein Introduction 195 General Concept of SMPs 197 Classes of Degradable SMPs 201 Covalent Networks with Crystallizable Switching Domains, Ttrans = Tm 202 Covalent Networks with Amorphous Switching Domains, Ttrans = Tg 204 Physical Networks with Crystallizable Switching Domains, Ttrans = Tm 205 Physical Networks with Amorphous Switching Domains, Ttrans = Tg 208 Applications of Biodegradable SMPs 209 Surgery and Medical Devices 209 Drug Release Systems 210 References 212 8.1 8.2 8.3 8.3.1 8.3.2 8.3.3 8.3.4 8.4 8.4.1 8.4.2 9.1 9.1.1 9.1.2 9.1.3 9.1.4 9.2 9.2.1 9.2.1.1 9.2.1.2 9.2.2 9.2.2.1 Biodegradable Elastic Hydrogels for Tissue Expander Application 217 Thanh Huyen Tran, John Garner, Yourong Fu, Kinam Park, and Kang Moo Huh Introduction 217 Hydrogels 217 Elastic Hydrogels 217 History of Elastic Hydrogels as Biomaterials 218 Elasticity of Hydrogel for Tissue Application 219 Synthesis of Elastic Hydrogels 220 Chemical Elastic Hydrogels 220 Polymerization of Water-Soluble Monomers in the Presence of Crosslinking Agents 220 Crosslinking of Water-Soluble Polymers 221 Physical Elastic Hydrogels 222 Formation of Physical Elastic Hydrogels via Hydrogen Bonding 222 IX 16.4 Enhanced Oxo-biodegradation of Polyolefins be effectively obtained by the fractionation of pre-aged specimens using solvent extraction This procedure may also provide, especially if carried out by using solvents with different polarities, further information on the relative amounts of different classes (e.g., carboxylates, alkanes, etc.) of degradation products deriving from peroxidation and cleavage of PE chains 16.4.2 Standard Tests Further to the evaluation of the abiotic oxidation of “degradable” PE, the final step to be investigated in order to envisage the ultimate environmental fate of these materials is the estimation of the extent of biodegradation under different conditions The requirement of two steps, abiotic and biotic, in the degradation mechanism of oxo-biodegradable plastic materials has recently led to the preparation and approval of ASTM D6954-04 “Standard guide for exposing and testing plastics that degrade in the environment by a combination of oxidation and biodegradation” [4] This standard provides a framework to assess and compare the degree of degradation attainable under controlled thermal and photooxidation tests as well as the degree of biodegradation and ecological impacts in defined environments after abiotic degradation Evaluations in ASTM D6954-04 are divided into three levels relevant to: (i) accelerated aging in standard tests for both thermal- and photooxidations and determination of the degree of abiotic degradation (Tier 1); (ii) measuring biodegradation (Tier 2); (iii) assessing the ecological impact after these processes (Tier 3) In order to implement Tier 1, the standard suggests the use of test conditions for thermal or photooxidation likely to occur in application and disposal environments for which the test material is designed In other words, accelerated oxidation should be carried out at temperatures and humidity ranges typical of application and disposal conditions Test materials resulting from the accelerated oxidation tests are therefore exposed to appropriate use or disposal environments (soil, landfill, compost) in standard respirometric (biometric) tests in order to assess the rate and the degree of biodegradation (Tier 2) Finally, any residues of the materials under test, deriving from both the abiotic oxidation stage and the biodegradation tests must be submitted to ecotoxicity tests to demonstrate their ultimate environmental compatibility (Tier 3) As a case study, the oxo-biodegradation behavior of LDPE blown film containing proprietary prodegradant1) additives has been reported In accordance with the general scheme of oxo-biodegradation, the study has been divided into two stages: (i) Tier represented by the abiotic pre-treatment and structural characterization of the sample, and (ii) Tier in which the ultimate biodegradation of the oxidized LDPE sample has been evaluated under different environmental conditions Finally, the relationship between the degree of oxidation achieved during the abiotic oxidizing step and the propensity to biodegradation has been established As repeatedly reported, the general mechanism of thermal or photooxidation is 1) Various patents assigned to EPI-Environmental Products Inc – Vancouver, Canada 391 392 16 Oxo-biodegradable Polymers Table 16.1 Structural changes recordable during the oxidation process of oxo-biodegradable polyolefins Parameters to be monitored during the preaging of LDPE Parameter Meaning Weight variation Increase: oxygen uptake Decrease: loss of volatile intermediates Carbonyl index by FTIR Formation of cleavable oxidized groups in the main chain Preliminary characterization of the oxidized functional groups Wettability Formation of an oxidized polar group at the surface Increase: raise of the propensity to microbial colonization Molecular weight Evaluation of the degree of chain scissions Decrease: raise of the propensity to microbial attack Fractionation by solvent extraction Estimation of the level of degradation Characterization of oxidized intermediates best described as an autocatalytic radical chain reaction leading to the oxidation and scission of polymer molecules, with the concomitant formation of oxidized low-molecular-weight fragments The parameters reported in Table 16.1 have been monitored during the preaging step carried out at 70 °C in an air convection oven After an induction period, an appreciable weight increase according to a sigmoidal profile, attributable to the uptake of oxygen, is observed Subsequently, as a result of prolonged treatment time, the sample weight starts to decrease owing to the loss of volatile (i.e., low molecular weight) degradation products Since the carbonyl groups usually account for most of the oxidation products of the thermooxidative degradation of PE, the concentration of carbonyl groups on oxidation products, as determined from the COi, can be used in monitoring the progress of degradation [40] In line with the recorded weight increase, the COi also shows a sigmoidal increasing shape In addition, FTIR spectroscopy shows progressive broadening in the 1700– 1780 cm−1 range for carbonyl groups with overlapping bands corresponding to carboxylic acids (1712 cm−1), ketones (1723 cm−1), aldehydes (1730 cm−1), and esters (1740 cm−1) during the aging period, thus indicating the formation of different oxidation products as aging progresses, as reported previously [41] The increase in surface wettability during the oxidation of PE film containing prodegradant is an important indicator of the loss in hydrophobic character of this plastic It has been shown that a few days of thermal treatment at 70 °C is sufficient to cause a dramatic decay in the contact angle of the LDPE film surface as hydrophobicity decreases In addition, as a result of thermal oxidation, bulk density increases and film disintegration is observed, by floating the test film in tap water 16.4 Enhanced Oxo-biodegradation of Polyolefins 160 Mw (kD) 120 80 40 0 cov Figure 16.3 Molecular weight versus carbonyl index (COi) relationship in LDPE film sample thermally treated in air in oven at 70 °C The disintegration of film samples occurred within 28 days, with film debris tending to sink to the bottom of the vessel In parallel with the advancing oxidation process as monitored by COi, weight changes and wettability increase during thermal degradation; a dramatic decrease in the molecular weight of the test sample has been recorded after a few days of oven aging The progressive shift toward lower molecular weights as the COi increases with the aging time can be observed by HT-GPC analysis The relationship between the Mw and COi can be expressed by a mono-exponential trend (Figure 16.3) Accordingly, COi values may be used in order to predict the Mw decrease as a function of the level of oxidation Moreover, the recorded trend is in agreement with a statistical chain scission mechanism, as suggested for the thermal- and photodegradation of polyolefins [13] The feasibility to separate oxidized LDPE films into high- and low-molecularweight fractions using a relatively simple extraction procedure with acetone has also been demonstrated [16] In particular, the level of oxidation, as related to the carbonyl index, illustrates the increase in the amount of the solvent extractable fraction in parallel with a significant decrease in molecular weight Accordingly, from heavily oxidized test samples, more that 25% by weight of acetone extracts can be obtained, thus also showing a very low Mw (0.85–1.05 kDa) (Figure 16.2) These data once more confirm that LDPE containing prodegradant additives can be effectively oxidized and massively degraded to low molar mass fractions which, owing to their wettability and polar functionality, become vulnerable to microorganisms 16.4.3 Biometric Measurements The second stage in the assessment of the environmental fate of “degradable” polyolefins is the evaluation of the ultimate biodegradation of them under different test conditions aimed at reproducing disposal or accidental littering environments 393 16 Oxo-biodegradable Polymers 80 70 60 Mineralization (%) 394 50 40 30 Filter paper TD-LDPE run (75 mg/g soil) TD-LDPE run (35 mg/g soil) Docosane 20 10 0 100 200 300 400 500 600 700 800 Incubation time (days) Figure 16.4 Mineralization profiles of thermally oxidized LDPE films and cellulose in a soil burial respirometric test In this connection, by using the materials retrieved from different abiotic degradation tests, several biometric respirometric tests have been carried out The aim was to assess the susceptibility to mineralization under test conditions representative of soil, compost, and river water environments of LDPE that had reached different degrees of oxidation during the abiotic degradation stage Highly reproducible results have been obtained from several biodegradation tests carried out in soil burial biometer flasks aimed at assessing the biodegradation behavior of thermally oxidized LDPE film samples [42] In all cases, the mineralization in soil of thermally oxidized samples does not show appreciable lag phases but it tends to a first plateau at about 5–7% mineralization in a few weeks (Figure 16.4) After that, a prolonged stasis (4–6 months) in the microbial conversion to CO2 of the carbon in the samples has been observed repeatedly before further and markedly exponential increases in the biodegradation rate Fairly high (55–65%) degrees of mineralization are observed after 18–24 months of incubation at room temperature This two-step biodegradation behavior of thermally oxidized LDPE samples has been observed also in mature compost biodegradation tests Therefore, in contrast to previous studies [41, 43] showing only limited and slow conversion to CO2 of UV-irradiated LDPE samples, samples with no preaging and additive-free LDPE samples in natural soils, very large degrees of mineralization have been recorded although these were obtained over a relatively long time frame ranging between 22 and 30 months [42] The first exponential phase, occurring during the first days of incubation in the biodegradation of thermally oxidized LDPE in soil, could be attributed to the fast assimilation by soil microorganisms of low-molecular-weight oxidized intermediates whose formation on the film surfaces has been demonstrated by the increased 16.5 Processability and Recovery of Oxo-biodegradable Polyolefins wettability observed during the abiotic stage of degradation The ready biodegradability of these compounds has been suggested previously because they disappear once oxidized samples are incubated in the presence of hydrocarbon-degrading microorganisms such as Arthrobacter paraffineus [20, 40, 44, 45] Additional support for this hypothesis is obtained from the FTIR characterization of the LDPE films exposed for a few months to soil microorganisms during biometric tests Indeed, a significant reduction of the absorbance in the carbonyl region with respect to the values recorded at the beginning of the test has been observed repeatedly In contrast, the number of double bonds in the carbon–carbon polymer chains was found to increase during the soil burial experiments, with a corresponding dramatic change in the fingerprint region of the IR spectra of the LDPE samples These observations suggest that, during the soil burial tests, preoxidized LDPE samples undergo an ongoing degradation process, mediated by both abiotic and biological factors, which leads to the formation of large amounts of oxidized molecular fragments capable of being assimilated as carbon sources by soil microorganisms This might explain the two-step biodegradation behavior that has been observed repeatedly for preoxidized PE films in soil The effect of different levels of oxidation as reached during the preaging (e.g., thermal degradation) step on the biodegradation propensity has also been evaluated in respirometric tests carried out in an aqueous medium in the presence of river water microbial populations The complex biodegradation profile characterized by the presence of alternating plateau and exponential phases has been observed in this case also, which suggests that this behavior can be considered as typical of the biodegradation of oxidized LDPE A straightforward relationship between the level of oxidation as determined by COi and the biodegradation behavior of thermally oxidized LDPE samples has been observed also in biodegradation tests carried out in an aqueous medium [46] In this experiment, heavily oxidized fractions of thermally degraded LDPE films as well as LDPE films having medium and high COi values were supplied as the sole energy and carbon source in a mineral salt medium to a microbial consortium obtained from a river water sample During incubation for 140 days at room temperature, degrees of mineralization ranging between 10% and 50% were recorded in the case of thermally oxidized LDPE samples having COi values between 4.6 and 20.7, respectively (Figure 16.5) Negligible mineralization was observed in the case of lightly oxidized LDPE with a COi value of only 2.3 These data also suggest, therefore, that readily biodegradable oxidized LDPE samples can be obtained, depending on the level of oxidation reached during the abiotic pretreatment 16.5 Processability and Recovery of Oxo-biodegradable Polyolefins The use of activating additives of the types described above does not affect the processing characteristics of conventional polyolefin resins These are “run” on the usual equipment at normal speeds The products are indistinguishable from 395 16 Oxo-biodegradable Polymers 60 COi 20.7 6.4 4.6 2.3 50 Mineralization (%) 396 40 30 20 10 0 30 60 90 120 150 Incubation time (days) Figure 16.5 Mineralization profiles of thermally oxidized LDPE materials having different levels of oxidation in aqueous respirometric tests the same products made without the prodegradant additives The oxo-biodegradable technology adds yet another desirable characteristic to the long list of useful properties for which the polyolefins are well known This technology also provides environmental benefits at nominal extra cost that consumers would like to support but are usually reluctant to pay much of a premium for In many countries there are formal as well as informal programs for recycling postconsumer plastics The recycling of used plastics can be a significant challenge, [47] but it is an important part of striving for a sustainable society It is significant therefore to note that EPI’s TDPA–PE materials, in spite of being oxobiodegradable, can be recycled with regular PE recycling operations This is because the prodegradants involved are not just simple oxidizing agents The former not affect the properties of the plastic until something else, for example, heat or UV light, initiates oxidative degradation, and this will not occur until all the antioxidants are consumed 16.6 Concluding Remarks For a number of decades, the polyolefins have been among the most useful and versatile materials This is because they have a wide variety of desirable properties and are relatively inexpensive In order to provide for years of reliable service, especially outdoors, it has been necessary to determine the kinetics and mechanisms by which polyolefins lose their useful properties over time, that is, to elucidate the details of oxidative degradation On the basis of this fundamental References information, highly effective stabilizers (e.g., radical scavengers, peroxide decomposers, UV absorbers) have been developed; they are used extensively in a wide variety of commercial formulations More recently, the demand for polyolefin products having a shorter lifetime has arisen, primarily in single-use packaging applications but also for a variety of agricultural products and in hygiene applications As a result, oxo-biodegradable polyolefins have been invented and developed These “clever” products are based on the following principles (i) The actual requirement is for polyolefins having controlled lifetimes, that is, shelf life/use life combinations that can be varied between a few months and several years, depending on the formulation (ii) In order to achieve such controlled lifetimes, it is required to enhance the rate of oxidative degradation – after the polyolefin articles have been used and discarded – by several orders of magnitude This cannot be done simply by adding an oxidizing agent or by omitting the addition of stabilizers It is being done by adding transition metal/fatty acid salts in catalytic quantities to conventional polyolefin resins prior to product fabrication These salts catalyze the decomposition of hydroperoxide groups attached to the polymer molecules, but only after stabilizing additives in the resins have been depleted (iii) Polyolefins are resistant to biodegradation by naturally occurring microorganisms, but their degradation products are biodegradable (iv) The combination of abiotic oxidation and biodegradation provides for the required shelf life/use life values and sufficiently rapid bioassimilation to avoid the buildup of discarded plastics in a variety of environments The oxo-biodegradation of suitable polyolefin formulations when buried in soil occurs at rates which permit the retention and use of as-produced biomass; (v) no toxic byproducts are produced in either the abiotic or subsequent biotic 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polycondensation (AP) 114f addition 57 aerodigestive tract (ADT) 321f., 324f., 331 alginate 156ff – chemical structure 156 – depolimerization 157 – derivative 158 – medical application 158 – physicochemical properties 156 alginic acid gel 157 aliphatic-aromatic polyanhydride 49 aliphatic diacid aliphatic poly(ester amide) 149ff aliphatic polyanhydride 62 aliphatic polyester 107, 125 α-amino acid (α-AA) 107ff., 150 – derivatives 151 – orientations 109 – structure 108 α-hydroxy acid (α-HA) 107, 150 – derivatives 151 Alzheimer’s disease 71 amino acid-based biodegradable polymer (AABBP) 109ff – application 124 – biodegradation 121ff – biocompatibility 123f – monomers 109 – properties 121f – solubility 121 – structure 115ff – synthesis 111ff., 115ff – transformation 115ff., 119 amino acid-based polyanhydride 51 amorphous switching domain 204, 208 anastomosis 313 animal model 324ff Arabidopsis thaliana 32 arginine-based PEA (Arg-PEA) 124f aromatic polyanhydride 46f articular cartilage 357 artificial trachea 317 assimiliation 394 Aureobasidium pullulans 180 b bacteroide 24 biocompatibility 65, 243f., 312, 322f biodegradability 29ff., 187, 264ff biodegradable biomaterial biodegradable plastic 380f biodegradable polyester 23ff., 77, 107ff., 125 biodegradable polymer 263ff., 354ff., 363ff biodegradable stents 314 biodegradation 33, 140ff., 155, 243f., 259, 264 – aerobic 266 – anaerobic 266 – analytical methods for monitoring 263ff biodegradation environment 268 biofunctionality 323 biomass 263, 265ff., 272ff biomaterial 1, 155 biometric measurement 393 biopolymer 2, 23, 356 biosynthesis 27, 29ff 1,3-bis(carboxyphenoxy)hexane (CPH) 46 1,3-bis(carboxyphenoxy)propane (CPP) 46, 368f bis-electrophile 111 2,2-bis(hydroxymethyl)propanoic acid (bis-HMPA) 246, 248 Handbook of Biodegradable Polymers: Synthesis, Characterization and Applications, First Edition Edited by Andreas Lendlein, Adam Sisson © 2011 Wiley-VCH Verlag GmbH & Co KGaA Published 2011 by Wiley-VCH Verlag GmbH & Co KGaA 400 Index bis-nucleophilic monomer 109 blend 55 block copolymer 10, 92f bone 345 bone marrow cell (BMC) 359 bone morphogenetic protein (BMP) 346 bovine serum albumin (BSA) 91 brain tumor 69 bulk degradation 12 butanediol (BD) 207f c calcium alginate (CA) 158f., 187 calcium phosphate 357 carbohydrate derivative 152 carbohydrates 155ff carbomethylpullulan (CMP) 181f carbonyl index (COi) 386, 389f., 392f., 395 carcinogenicity study 66 caries 171 carrageenan 160ff cascade-releasing dendrimer 238f catalyst cellulose 162ff., 184 – biosynthesis 162 – chemical modification 163 – crystal structure 162 cellulose ester 163 chemical crosslinking 52 chemical oxygen demand (COD) 271f chemotherapy-induced nausea and vomiting (CINV) 99 chitin 148, 165ff – biochemical properties 168 – chemical structure 166 – dissolution 167 – solubility 168 chitinase 167 chitosan 148, 161, 165ff – biochemical properties 168 – chemical structure 166 clevable shell 246 clinical trial 78, 100ff., 314 compensatory regeneration 347f controlled drug delivery 55, 68, 142 controlled lifetime 389, 397 copolymer 54, 156, 202 copolymerization 3, 10, 221 covalent polymer network 203f covalently crosslinked polyester 11 crosslinked polymer 81 crosslinker 11, 81, 164, 179, 221, 223 crosslinking 52, 82, 173, 221 crosslinking agent 220 crystallinity 7f., 13, 33, 45, 58f., 61 crystallizable switching domain 202, 205 cultivation 287 Cupriavidus necator 26, 29ff cytotoxicity 65 d deformability 198 deformation 200f degradable implant material 310 degradation 9, 12ff., 233, 264 degradation rate 13, 265, 291, 293, 298, 302, 306, 366 degradation time 14 dehydrochlorination 56 delivery system 67f , 99 dendrimer 237ff – biological implications 256ff – degradation 239, 252 – designing 240ff – multivalent PEGylated dendrimer 246, 249 dendritic polyglycerol (dPG) 240 dendritic polymer 237ff dendritic prodrug 243, 245 depolymerase 26f depolymerization 140 designer polymer 45 dextran 169ff dextranase 170 dextrose 170 diabetic foot ulcer (DFU) 158f dicarboxylic acid active diester (DAD) 111ff dicarboxylic acid dichloride (DDC) 111, 113 differential scanning calorimetry (DSC) 139 diisocyanate 134, 139, 145 diketene acetal 80, 102 diol 84f dissolved organic carbon (DOC) 269, 272, 274 distraction osteogenesis (DO) 330 diurethanediol (DUD) 145f DNA plasmid 93f – delivery 93 – stability 94 dog study 101 doxorubicin (DOX) 243, 246ff., 250f., 257 drug carrier 240 drug delivery 81f., 86, 91, 99, 186 drug delivery system 144, 237, 363ff Index – clinical need 364f – peptide-based drug delivery systems 375f drug release system 164, 201, 210ff dynamic mechanical analysis at varied temperature (DMTA) 205 e egg box model 157 elastic hydrogel 217ff – application 229f – chemical elastic hydrogels 220 – degradation 229 – history 218 – mechanical property 225 – physical elastic hydrogels 222ff – physical properties 225ff – swelling property 227f – synthesis 220 elasticity 9, 226 elimination 64, 240 embryo morphogenesis 343f., 351 endogenous depolymerization 295ff – analysis 295ff – modeling 295ff enzymatic degradation 14, 299 enzyme assay 269f – application 269 – drawback 270 – principle 269 epithelialization 317ff epithelium 319 epoxy-PEAs 120 epthelial-mesenchymal interaction 318 erosion 63, 79, 90, 93 erosion kinetics 12ff exogenous depolymerization 284ff – analysis 284ff – modeling 284ff – numerical study 288 extracellular matrix (ECM) 347, 350ff., 361, 371ff extraction 34ff extruded strand 91 f fatty acid-based polyanhydride 49f., 61 fibroblast 318f field trial 275 fingertip 344 5-fluorouracil (5-FU) 95 Fourier transform infrared (FTIR) spectroscopy 384ff., 390, 392, 395 fungi 141, 166, 182 g galactomannan 174 gas evolution test 272 – application 272 – principle 272 – suitability 273 gellan 171ff gel-like material 96ff gene therapy 70 gentamicin 70 glass transition temperature 84f., 103 glioma 69 glycosyltransferase 169 Gram-negative bacteria 29, 141, 172 Gram-positive bacteria 141 granisetron 100ff granule 26, 28 growth factor 348f guar gum 174ff – enzymatic hydrolysis 175 – material properties 175 – structure 174 – synthesis 176 G-unit 157 h head surgery 311, 320ff., 331 homopolymer 24 HPLC analysis 288f., 307 hyaluronan 176ff., 320 – biological function 177 – chemical modification 179 – chemical structure 177 – clinical application 178f – synthesis 177 hyaluronic acid (HyA), see hyaluronan hyaluronidase 178 hydrogel 183f., 217ff., 230, 315 hydrogen bonding 222f hydrolysis 77, 196 hydroperoxide 382ff., 387ff., 397 hydrophilic polymer 87 hydrophobic interaction 224f hydrophobicity 242 hydroxyalkanoate (HA) 24 hydroxyapatite (HAP) 208 i implant material 309, 312, 314, 324ff., 331 – application 324 – functionalized implant materials 310 – stability 325 implant topography 322 401 402 Index implantation 66, 211, 326 inflammation 65f injectable bone 330 injection 67 interfacial polycondensation (IP) 111, 114 irradiation 87f., 98, 211, 316 irritation 65f isophthalic acid (IPA) 46 ivermectin 81f., 104 3-ketothiolase 31f microorganism 287, 306 microphase separation 138 microsphere 54 mineralization 140, 263, 394, 396 minimal invasive surgery (MIS) 195f., 209f minocycline 69 molecular weight 33, 86f monofunctional alcohol 96 monomeric composition 33 multiblock copolymer 9, 210, 231 – morphology 10 – preparation 10 multivalancy 259f mutagenicity 66 l n laboratory-scale simulated accelerating environment 274 – application 274 – drawback 275 – principle 274 lactic acid 88f latent acid 83, 88, 90f limb regeneration 342f linear dendrimer 238 linker 251 low-density polyethylene (LDPE) 384, 386, 391, 393f., 396 lyase 173 N-acetyl-D-glucosamine (GlcNAc) 176 nanobiocomposite 16 nanofabrication 16f nanomedicine 259 nanoparticle 17, 182, 372 nanovehicle 17, 237 natural environment 275 neck surgery 311, 320ff., 331 neurological disorder 71 numerical simulation 283, 302, 305ff j junction zone 222 k m macrodiol 135, 139, 141 mandible 358 marine brown algae 156 material property mathematical model 283ff., 288, 300, 306 matrix metalloprotease (MMP) 321f., 324 medical device 209 melt condensation 56, 58 mepivacaine 78, 99f., 104 metal-free synthetic process methotrexate (MTX) 243 methyl methacrylate (MMA) 231f methylene-bis(4-phenylisocyanate) (MDI) 207f microbial activity 268 microbial cellulose (MC) 164f – application 165 – chemical structure 164f microbial depolymerization 283ff microdomain 138 microencapsulation 94 microfabricated device 373f o organogenesis 342, 350f ossification 345f osteogenesis 345ff osteomyelitis 70 oxidation 285 oxo-biodegradable polymers 379ff oxycellulose 162 p particulate cancellous bone and marrow (PCBM) 358f PEGylation 246, 248ff., 253f penetration 287 pentachlorophenol (PCP) 250 PHA depolymerase 28, 33 PHA granules 28 PHA synthase 27f., 31 pharmacokinetics 259 pharyngeal defect 320 phasins 27f photocrosslinking 52 photooxidation 383f., 387ff., 391 photopolymerization 15, 52 physical network 205, 208 plate test 270 Index – application 270 – drawback 270 – principle 270 poly(α-amino acid) (PAA) 108, 150 poly(α-hydroxy acid) 376 poly(α-hydroxyl acid) 363, 365ff poly(amidoamine) (PAMAM) 244, 257f poly(β-hydroxybutyrate) 24 poly(CPP) 53, 58, 62 poly(depsipeptide) (PDP) 116, 150 poly (ε-caprolactone) (PCL) 8f., 144f., 202f., 205, 219, 224, 229, 356 poly(ester amide) (PEA) 109, 111, 115ff., 133 – brush-like PEA 117 – epoxy-PEA 117 – functional PEA 116 – hydroxyl-containing PEA 118 – regular PEA 115, 151 – unsaturated PEA 117 – water-soluble PEA 118 poly(ester urea) (PEU) 119, 126f poly(ester urethane) (PEUR) 119, 126f., 205 poly(ether-anhydride) 49 poly(glycerol-succinic acid) (PGLSA) 240f poly(3-hydroxybutyrate) (P[3HB]) 23f., 29ff – biodegradability 29ff – biosynthesis 29ff – x-ray studies 26 poly(hydroxycarboxylic acid) 2, 8, 13 poly(3-hydroxyoctanoate) (P[3HO]) 26f poly(D,L-lactide) (PDLLA) 208f poly[(L-lactide)-co-glycolide] (PLGA) 314f., 365ff., 372ff poly[(L-lactide)-ran-glycolide] (PLG) 204, 212 poly(methyl methacrylate) (PMMA) 309 poly(ortho ester) (POE) 15, 77ff., 82ff., 104 – families 78ff poly(p-dioxanone) (PPDO) 206 poly(propylene fumarate) 15 poly(propylene oxide) (PPO) 218, 224 poly(tetramethyleneoxide) (PTHF) 208 polyacid 116 polyamide (PA) 108 polyanhydride (PA) 6f., 45ff., 363, 368f – biomedical application 68ff – chemical structures 47f – degradation 45 – elimination 64f – erosion 63 – in vitro degradation 63ff – mechanical properties 55, 58ff – physical properties 55 – physicochemical properties 59f – production 68 – stability 62 – synthesis 55ff – synthetic methods – thermal properties 58ff – toxicological aspects 65ff – types 46f – world market 68 polyAspirin 53 polycarbonate-based polyurethane (PCU) 147 polycations 116 polycondensation 57 polydepsipeptides 14f polydioxanone polyester 1ff., 23ff – alternative polyesters 14f – biomedical application 1f – complex architectures 15f – degradation mechanisms 12ff – enzyme-catalyzed synthesis – physical properties 7ff – preparative methods 3ff polyester-based polyurethane 136, 141f., 146 polyether-based urethane 136 polyethylene (PE) 283, 379, 381f., 384f., 387, 389, 395, 396 polyethylene glycol (PEG) 49, 91ff., 115, 136, 145, 204, 219, 223, 229, 244, 249, 283f., 370f., 374 – aerobic metabolism 286 – anaerobic metabolism 286 – biodegradation 287 polyethyleneimine (PEI) 244, 258 polyglycerol (PG) 238, 240 polyglycolic acid (PGA) 365 polyglycolide 2, 8, 355 polyhedral oligosilsesquioxane (POSS) 203, 207 polyhydroxyalkanoate (PHA) 2, 23ff – biosynthesis 25 – biosynthesis on microorganisms 29ff – granules morphology 26ff – extraction 34 – industrial production 25 – mechanical properties 36f – methods for extraction 35 – microbial degradation 33 – physical properties 36f – plants as producers 32f – recovery 34 403 404 Index – synthesis 3ff – thermal properties 36f polyketal 371 polylactic acid (PLA) 49, 51f., 300ff., 307, 356, 365 – analysis of enzymatic depolymerization 300ff – simulation of endogenous depolymerization 302ff polylactide 4f poly(lactide-co-caprolactone) 229 polylactide synthesis – mechanisms – stereochemical possibilities polylysine 250, 253f polymer degradation 266ff – biological degradation 267 – measuring 267ff – mechanisms 266ff – nonbiological degradation 266 polymer-drug conjugate 373ff polymer hydrolysate 100 polymer hydrolysis 88ff polymer implant 66, 309 polymer molecular weight control 96f polymer stability 98 polymer sterilization 87 polymer storage stability 87 polymer synthesis 79f., 82f polymeric drug 118 polymerization 3ff., 32, 57 polyolefin 380ff., 389 – abiotic oxidation 382ff – biodegradation of oxidation products 390f., 397 – enhanced oxo-biodegradation 387 – oxidation products 384ff – peroxidation 383 – processability and recovery 395 polypropylene (PP) 382, 384, 387 polysaccharides 16, 155, 180, 186 polysebacic acid (PSA) 46f., 49, 58, 62 polysuccinate 115 polyurethanase 142 polyurethane (PUR) 133ff – applications 142ff – biodegradation mechanisms 140ff – biomedical application 142, 145 – cardiovascular applications 143 – chemistry 134ff – enzymatic synthesis 146 – musculoskeletal applications 143 – neurological applications 144 – polymerization trends 145ff – properties 134ff – segmented PURs 137f – synthesis 139 polyvinyl alcohol (PVA) 284, 295, 306 preclinical toxicology 100 primary cell culture 321 prodrug 245, 250, 257 propylene glycol alginate 158 pullulan 180ff – chemical structure 180 – medical application 181 – modifications 181 pullulanase 181 r RA-based polyanhydride 49ff radical chain reaction 388 radioactively labeled polymers 273 – application 273 – drawback 273 – principle 273 rat study 101 rearrangement 80 reconstructive surgery 231 recovery 34ff regenerative biology 342 regenerative medicine 259, 309ff., 320, 329ff renewable source 147 respiration test 271 – application 271 – principle 271 – suitability 271 ricinoleic acid (RA) 49 ricinoleic acid-maleate (RAM) 50 ricinoleic lactone 50f ring-expansion mechanism 11 ring-opening polymerization (ROP) 3, 5, 50f., 57, 202, 204, 206 s SALEN (silacylimine) ligand salicylate-based polyanhydrides 53 scaffold 142f., 341ff., 350, 361 – architecture 353f – clinical application 357 – structure 352ff scleraldehyde 183 scleroglucan 182ff – application 184 – chemical structure 183 seaweed 160 sebacic acid (SA) 46, 49ff., 54, 58, 64, 66, 368 Index secondary reaction 137 self-immolative dendrimer (SID) 242, 245, 257 shape-memory creation procedure (SMCP) 197f shape-memory effect (SME) 11, 195ff., 199, 203f., 211f.g shape-memory polymer (SMP) 195ff – application 201, 209ff – classes 201ff – degradation mechanism 201 – general concept 197ff – types 201ff shape-memory polyurethane (SMPU) 195, 207 silver 159 skin 125, 357 sodium alginate 160 solid polymer 86ff solution polymerization 56 starch 148 starch-based polyurethane 148 stem cell 329ff stenosis 314 stereoregularity 36 stereospecificity 33 sterilization 310f stomach 326 stress relaxation 226f succinic acid 54 succinic acid-based polyanhydride 54f sugar 147 surface erosion 12 surgery 209 swelling pressure 227f swelling ratio 228 salicylic acid 53 synthetic fibrin 371 synthetic polymers 355 t taxol 69 tensile strength 226 terephthalic acid (TA) 46 tetrahydrofuran (THF) 80ff theoretical oxygen demand (TOD) 271 thermal polycondensation (TP) 114 thermal transition temperature 7f thermomechanical test 198 thermoplastics 149ff time-dependent degradation rate 293 tissue engineering 142, 174, 187, 220, 229, 234, 315, 328ff., 341ff – biodegradable polymer 354ff – favorable environments 349 – minimum requirements 348ff tissue expander 217ff., 228, 231ff tissue regeneration 327, 352 tosic acid salt of amino acid/alkylene diester (TAAD) 109ff., 115 tracheal construct 315ff., 319 tracheal reconstruction 312ff tracheal scaffolds 317ff tracheal surgery 312ff transgenic plant 33 transition 198 triethylene glycol (TEG) 79 trigger 242, 247 tumor efficacy 256f u unsaturated PEA (UPEA) 117, 120 Urodeles 342f v vascular endothelial growth factor (VEGF) 347 vascular tissue 359f vascularization 328ff vegetable oil 147 vinyl-2-pyrrolidone (VP) 231f viscoaugmentation 178 viscoprotection 178 viscoseparation 178 viscosupplementation 178 viscosurgery 178 w water-in-oil (W/O) emulsion 370 water-in-oil-in-water (W/O/W) emulsion 370 water-soluble monomer 220f water-soluble polymer 221f weight distribution 292ff., 297, 301ff weight loss (WL) 122 wound instillation 100 wound repair 343f wound-healing process 165 x xanthan 184ff – application 186 – degradation 185 – synthesis 184 – viscosity 185 xenobiotic polymers 283ff 405 ... properties of the final polymer While the ring-opening polymerization of l,ldilactide or d,d-dilactide leads to isotactic polymers, the polymers of the rac-dilactide should consist mainly of isotactic... Transformation of AABBPs 119 Properties of AABBPs 121 MWs, Thermal, Mechanical Properties, and Solubility 121 Biodegradation of AABBPs 121 Biocompatibility of AABBPs 123 Some Applications of AABBPs... Puiggalí Abbreviations 133 Chemistry and Properties of Biodegradable Polyurethanes 134 Biodegradation Mechanisms of Polyurethanes 140 Applications of Biodegradable Polyurethanes 142 Scaffolds 142 Cardiovascular