Solid polymers, biodegradation

It would be very important that various types of interactions among macromolecular chains, which are related to Tm, are taken into consideration when designing the biodegradable solid polymers. 

Nomura, N., Deguchi, T., Shigeno-Akutsu, Y., Nakajima-Kambe, T., and Nakahara, T. (2001) Gene structures and catalytic mechanisms of microbial enzymes able to biodegrade the synthetic solid polymers nylon and polyester polyurethane. Biotechnol. Genet. Eng. Rev., 18,125-147. 

Overall, much effort has been made to develop biocompatible organic materials, which allows for the ultimate integration between the electronic device and biological system. The possibility of fabricating memory devices on biodegradable substrates, such as, rice paper and chitosan is also demonstrated. Biocompatible and flexible resistive switching memory devices are made on the basis of Ag-doped chitosan as the natural solid polymer electrolyte layer on the transparent and bendable substrate. Decomposable devices, where chitosan layer serves as the substrate while Mg as the electrode, have been also achieved (Hosseini and Lee, 2015). A comparison of the biocompatible material-based resistive switching memory devices is made in Table 3.2. 

Chin Han Chan, PhD, is an associate professor at the Faculty of Applied Sciences, Universiti Teknologi MARA [MARA University of Technology) in Selangor, Malaysia. She has received many research grants, has published many articles in professional journals, has published chapters in books, and has presented at many professional conferences. Her field of interest includes epoxidized natural rubber-based nanostructured blends, thermoplastic elastomer, biodegradable polyester/polyether blends, and solid polymer electrolytes. 

She has pnbhshed more than 45 papers in intematiorral and national refereed journals, more than 60 publications in conference proceedings, and more than 20 invited lectures for international conferences. She has been one of the editors of Malaysian Journal of Chemistry, Berita IKM- Chemistry in Malaysia, and books pnbhshed by Royal Society of Chemistry entitled Natural Rubber Materials, Volume 1 Blends and IPNs and Volume 2 Composites and Nanocomposites. She peer-reviews a few international journals on polymer science. Her research interest is devoted to modified natural rabber-based thermoplastic elastomers, biodegradable polyester/polyether blends, and solid polymer electrolytes... 

Several standard test protocols for measurement of polymer biodegradation are presently available. Organizations which have published such tests include the American Society for Testing and Materials (ASTM), Ministry of International Trade and Industry (MITI) (Japan) [40] and the Organization for Economic Cooperation and Development (OECD) [41]. They are, however, for the most part deficient to the extent that they have no control over the nature of microbial inoculum used, or the possible preadaptation of the mixed populations to specific substrates, and over the adequate control of particle size of the substrate. The relevance of these factors to laboratory assessment of the biodegradabUity of synthetic polymers has been recently discussed [1]. Most of these test methods have been derived from tests first used with detergents [42], and are not always well-suited for solid polymer substrates. 

Figure 21.9 Biodegradability testing of solid polymers [ItavaaraSc Vikman, as cited in 50 51].

Implants are solid polymers loaded with an active substance. The active substance is delivered at a constant rate as long as the implant stays at the administration site. Local or systemic activity can be achieved. The duration of activity varies from days to years. Insertion and removal (if not biodegradable) requires medical assistance [30]. 

Most biodegradable composites being tested employ a thermoplastic matrix. There are inherent difficulties in interfacial wetting between linear thermoplastics and reinforcing fibres which limit optimum stress transfer between the fibre and matrix. This also deleteriously affects hydrolytic stability [63]. While the use of solid polymer without fibre has been considered [24, 71-73],... 

D. Modified Semi-Quantitative Solid Surface Studies. The ASTM protocol for polymer biodegradation by fungus was modified for the studies involving the zinc chloride-containing polymer matrices. Zinc chloride (10% w/w) was dissolved in 2 mL acetone and added to the polymer solutions. Films were cast on the bottom of sterile petri dishes and the solvent allowed to evaporate. Warm glucose supplemented (1% w/w) BMS-agar (20 mL) was inoculated with 0.1 mL of the spore suspension and then poured over the surface of each polymer film. The plates were incubated at room temperature for two to four weeks after which the effect of the zinc on microbial growth was visually observed. 

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