Search

A series of novel processable and heat-resistant silicon-containing resins (PSA-E resins) were successfully synthesized by the reaction of 1,3,5-tris-(4-ethynylphenyl)benzene (TEPHB) with silylene-acetylene polymer (PSA resin) with high yields. The molecular structure, thermal curing processes and thermal properties were characterized by FTIR, 1HNMR, GPC, DSC and TGA. The results indicated that these novel resins could be melted at room temperature and thermally cured at 200–250 °C with low exothermal heat. Owing to the complete crosslinking of ethynyl groups, the Td5 (temperature of 5% weight loss) for all the thermosets are above 500 °C, and the overall char yields were above 87% at 900 °C under nitrogen.

A review of the major issues surrounding the postuse disposal of polymer composite materials is presented. Composites are compared to unreinforced plastics in terms of production volume and the technologies available for reprocessing. Not surprisingly, composites comprise a very small fraction of the plastics waste stream. In highvolume applications such as automobiles, however, there are reasons to be concerned about composites recycling. The fundamental categories of dealing with waste (burning, burying, reusing, or using less in the first place) are described in relation to plastics and composites. Reprocessing technologies with applications for composites are reviewed. For thermosetmatrix composites, processes involving regrinding waste materials and using them as filler for other polymer processes show promise. For thermoplasticmatrix composites, processes involving grinding and remolding by injection or compression molding are promising. Applications for recycled composites, without which reprocessing is futile, are also reviewed.