Poly ester group hydrolysis

The possibility exists that the acid used in hydrolysis could catalyze the hydrolysis of the succinic ester group in the middle of the telechelomer itself. Even though NMR ( H and C) cannot easily eliminate this possibility, we have evidence that such a hydrolysis did not take place. For instance, hydrolysis should result in the formation of poly(pivalolactone) which is insoluble both in methylene chloride and water, but no insolubles were evident. Also, the Gel Permeation Chromatograms do not show impurities in the product. 

Co-existence curves of the A-poly-2 copolymer before and after the hydrolysis of active ester groups indicated that, in both water and PBS, the copolymer with intact active esters had an LCST a few degrees lower (29 a 31 C) than that of the hydrolyzed copolymer (31 a 34 C). 

The ester functions of a polymer such as poly(vinyl acetate) are just like ester functions of simple molecules they can be cleaved by hydrolysis under either acidic or basic conditions. To prepare poly(vinyl alcohol), therefore, polymerize vinyl acetate to poly(vinyl acetate), and then cleave the ester groups by hydrolysis. 

By hydrolysis of the ester groups of the PMMA arms, an amphiphilic polyelectrolyte was obtained with PS arms and poly(methacrylic acid) (PMAA) arms. [98, 99] These particles are soluble in water, when using several sequential dialysis steps (starting from 1,4-dioxane). However, due to the non-polarity of both PB core and PS hemi-corona they collapse to a core... 

Alternatively, hyperbranched polymers can be prepared in situ on the monolayer surface. Treatment of the acid-terminated layer with chloroformate and amine-terminated poly(f-butyl acrylate) produces ester groups on the surface. Hydrolysis of the ester functions with tosic acid gives carboxyl groups. The whole procedure is then repeated several times... 

By hydrolysing a polyether PU, a polyether polyol is obtained with a similar structure to those of the initial virgin poly ether polyol. For polyester PU the hydrolysis reaction is more complicated because the esteric groups of polyesters are hydrolysed back to monomers, such as diacids and glycols or polyols (reaction 20.3). 

Polyisobutylene-b-poly(methacrylic acid) (PIB-b-PMAA) was prepared by hydrolysis of the ester group under acidic conditions, using HCl(aq) in dioxane. After hydrolysis a new amphiphilic diblock copolymer is formed as shown in Scheme 3. The resulting amphiphilic block copolymers form a stable polymeric emulsions in dioxane. 

Lambe et al. (1978) studied the enhanced steric stabilization of polystyrene latices by poly(vinyl alcohol). This is included in this sub-section on copolymers because the samples studied were not fully hydrolysed. This means that the parent poly(vinyl acetate) from which they were derived was only partially (88%) hydrolysed (this is often accomplished by alcoholysis). The resultant polymer is not, however, a completely random copolymer because adjacent group effects influence the hydrolysis kinetics in such a way that some degree of blockiness is introduced. On average, these blocks consist of 2 ester groups to every 18 alcohol groups but blocks of average size 5-6 acetate groups are common. The chemical structure of the polymers should therefore formally represented by a structure intermediate between poly(vinyl acetate-6-vinyl dcohol) and poly(vinyl acetate-co-vinyl alcohol) rather than poly(vinyl alcohol) as such. The random (or statistical) copolymer can be prepared by partial reacetylation of fully hydrolysed poly(vinyl alcohol). 

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