Biopolymers hydrolytic stability

Poly(a-hydroxy acids), poly(glycolic acid), poly(lactic acid), and their copolymers Perhaps the most heavily researched types of synthetic biopolymers are PLA, PGA, their copolymers PLGA, PCL, poly(propylene fumarate) (PPF), and PHB (Seal et al., 2001). The poly(a-hydroxy acids), including PLA and PGA are broken down to their monomeric units lactic acid and glycolic acid through hydrolysis of the ester bonds in their backbones. These breakdown products are then simply cleared by natural metabolic pathways. To maintain the hydrolytic stability of the ester bond as well... 

As well as the physical mechanism which may affect the degradation of biopolymer at elevated temperatures. Ash et al. (1983) discuss a number of other mechanisms including hydrolytic, free-radical and enzymatic mechanisms. With reference to the hydrolytic stability of xanthan. Ash et al. (1983) noted that the acetate group in xanthan is removed very readily at pH 12 even at room temperature. They also noted that a lower acetate content of xanthan has the effect of lowering the transition temperature. It has previously been reported that the viscosity of xanthan solutions is either increased (Jeanes et al, 1961) or is almost unaffected (Nisbet et al, 1982) by this loss of acetate groups. Ash et al (1983) concluded that the effect on solution viscosity of the loss of acetate may indeed be small but the... 

Vollmert [32], Aspinall [33], and Seright and Henrici [26] investigated the stability of biopolymers in alkaline conditions. Vollmert determined that polymers such as polysaccharides could be hydrolytically degraded with strong bases [32]. 

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