However, we note that these differences in ether versus ester linkages
played a minimal role in plasticization as this effect was attenuated by the dominance of the increasing chain length above n = 13.
Here, the polyurethane with polyester soft segments would degrade due to the hydrolysis of ester linkage
, which was independent of ship speed.
5 double bonds per each UV conjugated ester linkage
What is not well understood is the mechanism of attachment to the acceptor alcohol forming the necessary ester linkage
(in the case of ferulates in grasses the C5 hydroxyl of arabinosyl substitutions on arabinoxylans).
Whereas zinc compounds was also found inappropriate for hydrated environment as create alkaline conditions which are fatal for alkyd coatings as promote hydrolysis of ester linkage
in alkyd polymeric backbone.
This may be due to the presence of the ester linkage
in PNSu (S-S), which is easily susceptible to base-catalyzed attack.
The phenomenon was ascribed to the appearance of carbonyl stretching bands of ester linkage
However, the acceptor group can be either of; the carbonyl of urethane, urea linkage of the hard block, carbonyl of ester linkage
available in polyol soft segment, the oxygen atom of the ester/ether linkage when polyester/polyether are present in the soft segment.
Figure 4 shows a possible schematic of the modification reaction of the starch molecule, in which the starch ester may preferentially be formed by the reaction of the starch hydroxyl groups with MA to obtain an ester linkage
with pendent carboxylic groups (25).
A mixture of a phosphorus compound and an organic base is reported to undergo an amide and an ester linkage
under very mild conditions and its use has been extended to the synthesis of aliphatic and aromatic polyamides [41-42].
It was concluded that the flame resistance mechanism of LCPs can be attributed to the endothermic reaction at the ester linkage
rupture process, char formation and diluting oxygen by evolution of C[O.
Among these elastomers, the highest performance elastomers are thermoplastic polyester elastomers (TPE-E), also known as COPE and TPC-ET, which are essentially copolyether esters with alternating, random-length sequences of either long-chain or short-chain oxyalkalene glycols connected by ester linkages
2) preferably catalyse the hydrolysis of carboxyl ester linkages
composed of short-chain fatty acids only in aqueous solution, and they can also catalyse the ester synthesis and trans-esterification (Bornscheuer 2002, Holland et al.
Cyclic anhydride and protonated amide functional groups were identified as reaction intermediates, which resulted in carboxylic ester linkages
between MSO and cellulose upon elevated temperature curing.
Based on the results of Fourier transform infrared spectroscopy, ester linkages
between wood and citric acid were confirmed, especially at high moulding temperatures.