Natural polymers degradation

The author is unaware of any commerical polymers that are specifically designed to degrade oxidatively, although oxidation may be involved in association with hydrolytic and biological degradation. It may be of interest to note that before World War II products known as rubbones were produced by degrading natural rubber with cobalt linoleate in the presence of cellulosic materials to produce low molecular weight, fluid oxidised natural rubber (Section 30.4). 

Al-Malaika, S. and Amir, E.J., Thermoplastic elastomers Part III—Ageing and mechanical properties of natural rubber-reclaimed rubber/polypropylene systems and their role as solid phase dispersants in polypropylene/polyethylene blends, Polym. Degrad. Stab., 26, 31, 1989. 

Synthetic polymers and natural polymers suitable for drilling muds are listed in Tables 1-7 and 1-8, respectively. Polyacrylamides are eventually hydrolyzed in the course of time and temperature. This leads to a lack of tolerance toward electrolyte contamination and to a rapid degradation inducing a loss of their properties. Modifications of polyacrylamide structures have been proposed to postpone their thermal stability to higher temperatures. Monomers such as AMPS or sulfonated styrene/maleic anhydride can be used to prevent acrylamide comonomer from hydrolysis [92]. 

A product is only considered to be totally biodegradable if all its single components can be degraded naturally. Currently, pressure sensitive adhesives (PSA) are mostly based on non-biodegradable synthetic polymers such as polyacrylates, ethylene-vinyl acetate copolymers and styrene block copolymers [124]. Therefore there is a growing demand for the application of biodegradable PSAs on naturally degradable products like paper and cardboard. 

Most synthetic and natural polymers degrade when exposed to solar ultraviolet (UV) radiation (1-5). In synthetic polymers degradation is generally caused by the presence of photosensitive impurities and/or abnormal structural moieties which are introduced during polymerization or in the fashioning of the finished products. The presence of groups such as ketones, aldehydes, peroxides and hydroperoxides are implicated in polymer degradation (1-5). 

Naturally occurring polypeptide polymers degradable to mixtures of different amino acids. 

Filler surface chemistry is clearly important, although the effects vary widely according to the exact nature of the filler, polymer and surface modifier. Some of the factors that can influence toughness and are, at least in part, controlled by filler surface chemistry include the level of filler polymer interaction [40], the structure of heterophasic polymers [41], the amount of polymer degradation during compounding [42], filler dispersion [43] and polymer crystallinity arising from altered nucleation processes [44]. 

PB. Sulekha, R. Joseph, and K.E. George, Studies on polyisobutylene bound paraphenylene diamine antioxidant in natural rubber, Polym. Degrad. Stab., 63(2) 225-230, February 1999. 

Fig.9 Effect of initial tocopherol concentration and extrusion temperature on nature and distribution of Toe products formed in PP. (Reproduced with kind permission of Polym Degrad Stab, 1999, 65 143)...

TG-FTIR Vulcanisation [32], ageing characterisation [39, 48], sulphur components in rubber [31], polyurethanes [37], polymer degradation mechanisms [30, 40, 41], identification of base polymers [36, 43, 44], thermal stability [46], grafted flame retardants [47], differentiation of EVA rubbers [45] and AN-NBR rubbers [36, 44], degradation of chlorinated natural rubber [42],... 

Manfredi, L. B., Rodriguez, E. S., Wladyka-Przybylak, M., and Vazquez, A. Thermal degradation and fire resistance of unsaturated polyester, modified acrylic resins and their composites with natural fibres, Polym. Degrad. Stabil. 2006, 91, 255-261. 

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