JEC COMPOSITES MAGAZINE - Issue #61 - November/December 2010 - 40

cross-linking moiety, suggesting that hydrolysis could be dominant, ideally through suppressing the pyrolysis. It was reported that the pyrolysis of the styrene cross-linking moiety of the thermosetting polyester resin started at 230°C [I]. To suppress the pyrolysis, the reaction was conducted at 230°C and Fig.6: UP resin horizontal recycling from recovered glycol 2.8 MPa for 4 hours with calcium carbonate. Figure 8 shows the experimental results obtained at polymerized into polyester with new resin raw materials to 230°C. The reaction liquid obtained was clear. No substances produce recycled UP resin with molecular weight higher than derived from pyrolysis of the styrene cross-linking moiety were 4,000, that was used to produce an FRP board sample for observed. Several alkali catalysts were then examined under the strength-characteristic testing. The recovered glycol/new glycol same reaction conditions (230°C, 2.8 MPa for 4 hours) to ratio was 1:9. It showed strength characteristics equivalent to a improve the conversion. Table 4 shows that the highest new UP resin. conversion of 96.9% was achieved using potassium hydrate. The recovery rate of glycol and fumaric acid was 70.7% and 21.81% Enhanced recycling of the styrene-fumaric acid by weight, respectively. copolymer Molecular structure analysis of the SFC suggested that it has a Tab.4: Cleaned surface by different solvents : potential for various applications. In exploring the application, comparison between cotton cloth and presaturated wipes performances it was found that its molecular structure was similar to that of a Reaction Glycol Fumaric-acid Catalyst commercial LPA (low profile additive) comprising polystyrene ratio recovery ratio recovery ratio for FRP forming (Figure 7). g…/… FRP recycling in Europe, North America and the Pacific Rim area No Catalyst CaCO3 K3PO4 KOH 15.9% 30.8% 41.5% 96.9% 33.7% 32.2% 58.6% 70.7% 9.0% 1.2% 3.6%
Fig.7: Styrene-fumaric acid copolymer and a commercial low profile additive

FEATURE “Automotive”

Figure 5 shows the SFC extracted from the reaction liquid and its molecular formula. A molecular structure analysis of the SFC showed that the styrene/fumaric acid ratio was 2.2:1 and its molecular weight was approximately 30,000 [2]. The weight of SFC was 75% of the weight of the initial thermosetting resin. Thus, combining with glycol and fumaric acid, it was shown that up to 96 wt.% of the initial resin existed in the reaction liquid as reusable ingredients. It was obvious that hydrolysis was ideally dominant and the pyrolysis was almost suppressed in these reaction conditions.

Fig. 5: Styrene-fumaric acid copolymer

Horizontal recycling of UP resin

Figure 6 shows the experimental results of UP resin horizontal recycling from recovered glycol. The recovered glycol was

jec composites magazine / No61 November - December 2010
21.8%

The LPA is a high value-added additive used to suppress shrinkage during FRP forming. The LPA stores styrene before forming and releases it during forming, keeping the space occupied by styrene vacant to suppress shrinkage. Therefore, solubility in styrene is needed to generate a shrinkage control effect. The SFC was not soluble in the styrene monomer due to its hydrophilic group. Hydrophobic modification of the SFC using benzyl chloride as modification agent and tetra-n-butyl ammonium bromide as phase transfer catalyst was tried to add solubility in styrene. Figure 8 shows the modification reaction experiment result. A modified SFC – SBFC (styrene-benzyl fumarate copolymer) – was obtained. SMC (sheet moulding compound) sheets were produced with the resulting SBFC and the commercial LPA comprising polystyrene, inorganic filler and glass fibre to evaluate the shrinkage control effect. After cure of the SMC sheet, the

JEC COMPOSITES MAGAZINE - Issue #61 - November/December 2010

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #61 - November/December 2010