Several features of vinyl chloride-diallyl phthalate suspension copolymerization

Abstract

Vinyl chloride-diallyl phthalate (VC-DAP) suspension copolymerization was carried out in a 5-L autoclave and 200-mL stainless steel vessel at 45°C. The apparent reactivity ratios of VC-DAP suspension copolymerization system were calculated as r VC ϭ 0.77 and r DAP ϭ 0.37. It shows that VC-DAP copolymer contains no gel when the feed concentration of DAP ( f 2 0 ) is lower than a critical concentration ( f cr , inside the range of 0.466 -0.493 mmol/mol VC at 80 -85% conversion), the polymerization degree (DP) of copolymer increases with the increase of f 2 0 and conversion. VC-DAP copolymer is composed of gel and sol fractions when f 2 0 is larger than f cr . The DP of sol fraction decreases as f 2 0 increases, but the gel content and the crosslinking density of gel increase. The gel content also increases as conversion increases. The results also show that the index of polydispersity of molecular weight of sol changes with f 2 0 , a maximum value appears when f 2 0 is close to f cr .

Different photodegradation processes of PVC with different average degrees of polymerization

“…The primary chains contain many DAP units, PDBs, and double bonds; with UV‐irradiation, they have a higher probability of participating in chain crosslinking reaction. The molecular weight of the PVC primary chains that tended to crosslinking is much higher than that of the commercial vinyl chloride homopolymer 16. The rapid decrease of M η in all samples after 120 h indicates that prolongation of irradiation leads to predominant degradation.…”

“…When PDB is reinitiated by a radical and is bonded with another macromolecule by chance, DP may be increased as a result. The larger the macromolecule, the greater the number of DAP units and PDBs in a polymer chain 13, 16. So PVC (DP = 3000) contains carbonyl groups, double bonds, ether bonds, and so on, besides CC, CH, and CCl bonds.…”

Influences of diallyl phthalate as chain extender on the properties of high molecular weight poly(vinyl chloride) resin

“…Copolymerization has been used for the synthesis of various functional polymers such as styrene–divinylbenzene, cyclooctene–norbornene derivatives, vinyl acetate–methyl methacrylate, and glycidyl methacrylate–chlorinated polyethylene . Vinyl chloride (VC)–diallyl phthalate (DAP) suspension copolymerization has been recently reported . To prevent the release of toxic hydrogen chloride, the polymerization was conducted at relatively low temperatures by adding various inert plasticizers, such as dibutyl phthalate or DOP, resulting as usual in a soft PVC with rubber‐like elasticity.…”