The Synthesis And Properties Of Hydrogel-Containing Unsaturated Polyester Resin

Reverse suspension double-phase polymerization is defined as the polymerization of oil-soluble monomer and water-soluble monomer simultaneously or in succession, belonging to polymerization in-situ.Hydrogel-containing unsaturated polyester resin (HCUP-1&HCUP-2) was synthesized by reverse suspension double-phase polymerization, the dispersed phase of HCUP-1 is PSAA and the dispersed phase of HCUP-2 is P(SAA-AM). Triethanolamine(TEA)-SPAN80 was used as emulsification system. BPO-DMA(benzoyl peroxide and dimethylaniline) was used as solidification system. The influencing factor of mechanical performance, flame-retardant effect, water-retention rate and length-retention rate were studied, such as microcosmic morphology, volume fraction of dispersed phase and weight fraction of monomer in dispersed phase. In addition, unmodified unsaturated polyester resin(UPR) and water-containing unsaturated polyester resin(WCUP) were prepared, and HCUP-3 was prepared by nonsoap reverse suspension Double-Phase polymerization. HCUP-3 is the same as HCUP-1 except TEA and SPAN80, and the effect of neutralization degree, Al(OH)3 was studied on the properties of HCUP-3.Hydrogel with suitable chemical structure possesses good elasticity, comparatively high mechanical performance and water-retention rate so HCUP is better than WCUP in mechanical performance, flame-retardant effect, water-retention rate and length-retention rate. But HCUP-1 and HCUP-2 are lower than unmodified UPR in tensile strength and flexural strength, and higher than unmodified UPR in impact strength. HCUP-3 is higher than unmodified UPR in tensile strength and flexural strength, especially in flexural strength. HCUP-3(38.67MPa)is merely lower than unmodified UPR(46.7MPa) by 17% in flexural strength and appreciably lower than unmodified UPR in impact strength. The mechanism of high water-retention rate of hydrogel is that lots of hydrophilic groups are contained in hydrogel. Bound water and free water in hydrogel will not be squeezed out by pressure and hydrogel has lower dehydration rate than water in liquid state. Especially to HCUP-1, it's remarkable water-retention and enhancement of char leads to outstanding flame-retardance and LOI of HCUP-1 reaches to 34%. Unsaturated polyester resin with hydrogel possesses high LOI, non-toxicity, excellent smoke inhibition and low cost, and the effect in environmental protection is far better than flame-retardant with halogen.