Chemical Recycling of Class A Surface Quality Sheet-Molding Composites
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- 作者：Marie Vallee ; Gilles Tersac ; Nadè ; ge Destais-Orvoen ; and Gé ; rard Durand
- 刊名：Industrial & Engineering Chemistry Research
- 出版年：2004
- 出版时间：September 29, 2004
- 年：2004
- 卷：43
- 期：20
- 页码：6317 - 6324
- 全文大小：260K
- 年卷期：v.43,no.20(September 29, 2004)
- ISSN：1520-5045
文摘
This article describes the solvolysis of sheet-molding composites (SMC) consisting of anunsaturated polyester-styrene (UP) thermoset resin associated with glass fibers, filler (calciumcarbonate), and a low-profile additive (LPA) (thermoplastic poly(vinyl acetate)). Preliminarystudies have shown that glycols, diacids, and bisphenols are poor solvolytic reagents. On thecontrary amino alcohols and polyamines allow much higher depolymerization yields, leading toa total digestion of the polymers. Diethylenetriamine (DETA), at boiling temperature (205 
C)was then chosen as solvolytic reagent. Pure poly(vinyl acetate) (PVAc) is readily converted tosoluble products. A total dissolution of cured UP requires high yield of ester cleavage. Longerreaction times are needed with styrene content enhancing. The introduction of PVAc in the UPresin does not alter the kinetics of solvolysis of the thermoset but affects the rheological behaviorin intermediate states and enhances the viscosity of the final liquid. A greater effect is observedwith higher molecular weight poly(vinyl acetate). Treatment of SMC chips with DETA at 205C for 10-14 h leads to a mixture that can split into three fractions, viz. glass fibers, filler, andan organic liquid. Organic contamination of glass fibers and fillers is very low. The organic liquidmay be used as a curing agent for epoxy resins. The course of the solvolytic process is affectedby the nature of the LPA and the original sizing of the glass fibers.
C)was then chosen as solvolytic reagent. Pure poly(vinyl acetate) (PVAc) is readily converted tosoluble products. A total dissolution of cured UP requires high yield of ester cleavage. Longerreaction times are needed with styrene content enhancing. The introduction of PVAc in the UPresin does not alter the kinetics of solvolysis of the thermoset but affects the rheological behaviorin intermediate states and enhances the viscosity of the final liquid. A greater effect is observedwith higher molecular weight poly(vinyl acetate). Treatment of SMC chips with DETA at 205C for 10-14 h leads to a mixture that can split into three fractions, viz. glass fibers, filler, andan organic liquid. Organic contamination of glass fibers and fillers is very low. The organic liquidmay be used as a curing agent for epoxy resins. The course of the solvolytic process is affectedby the nature of the LPA and the original sizing of the glass fibers.