Unsaturated polyester crosslinked matrix

Figure 6.18 Production of an (ortho) unsaturated polyester crosslinked matrix...

The crosslinking copolymerization of unsaturated polyesters with styrene is utilized industrially for the production of surface coatings. More extensive are applications in fiber-reinforced plastics where the unsaturated polyesters are used as a matrix for inorganic and organic fibers (see Example 5-20). Areas of application are (large) parts in boats, vehicles, and sport equipment construction. 

Unsaturated polyesters (UPs) crosslinked with styrene are often used as a matrix of fiber reinforced plastics. Several reports treated the degradation of the crosslinked UPs with high temperature treatment in water (1,2), acetic acid (5), alcohols including glycols (4,5), and amines (6), often in the presence of catalysts. In these literatures, recovery of polymeric materials from the crosslinked UPs was not a main objective. However, in case we can hydrolyze polyester chains selectively, linear polystyrene derivatives can be obtained as recycled materials. 

The styrene crosslinking of unsaturated polyester resins is perhaps one of the most widely used reactions to form the matrix for fibreglass-reinforced composite materials. (The... 

Unsaturated polyester resins are produced by a crosslinking reaction in solution of a prepolymer dissolved in styrene initiated with peroxides. This curing reaction renders an insoluble and infusible crosslinked matrix with high rigidity, but fragile. This matrix is usually reinforced with glass fibers or fillers of micrometric size. Since the mechanical properties of such materials depend strongly on... 

Unsaturated polyesters, dissolved in greater or lesser quantities of styrene monomer, form the matrix material widely used for glass-fiber-reinforced thermoset sheet molding and bulk molding compounds. Upon polymerization of the styrene and concomitant conterminous grafting, an AB crosslinked copolymer network forms (see Section 5.6). 

The chemical resistance of polyester amide glass fibre composite is excellent [126]. A solvent mixture of CF3COOH/CHCI3 was used as a solvent for thermotropic LC polyester, based on 4-chlorocarbonyl phenyl esters of aromatic dicarboxylic acids and phenols or aliphatic diols for viscosity measurement. This indicates thermal stability in various organic solvents. [127]. Unsaturated aromatic LC polyesters, synthesized with the aim to fix the LC state, can be crosslinked by using styrene. The crosslinked matrix can be degraded by refluxing in 3 M aqueous sodium hydroxide solution and methanol in a vol. ratio of 3 2 [128]. 

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