New Reactive Diluents for an Environmentally Efficient Approach to Composite Repair.

摘要

The use of polymer matrix composites (PMCs) to replace metal components is providing DoD with a cost effective path to create lighter, more fuel efficient, and faster vehicles (land, sea, and air). In addition, PMCs do not suffer from the effects of corrosion like their metal counter parts so there is significant savings in maintenance over a component lifetime and DoD can avoid the use of toxic corrosion inhibiting coatings (e.g. chromium (VI)). One negative aspect to PMC production and repair is that volatile organic compounds (VOCs) are often produced during processing and cure of the PMC. Elimination of VOCs is a critical target and is pivotal for increasing PMC applications while decreasing their environmental footprint. Since repair work is often done in the field where environmental control is difficult, VOC elimination is especially important. In this limited scope program we were successful in preparing three new reactive diluents for use with vinyl ester resins. The new reactive diluents (RDs), 4-(4 - tributylsilylphenoxy)styrene (S1), (3-phenoxyphenyl)methyl methacrylate (A1), and 4- phenoxyphenyl methacrylate (A2) were prepared in quantities ranging from 12 to 100 g and each RD was fully characterized by analytical and spectroscopic methods. Each of the RDs prepared in this study possessed viscosities at approximately 100 cP and vapor emissions were reduced by 10,000+ times when compared to styrene. We found that S1 did not react well with the VE and this led to phase separation. In addition, S1 was found to be unreactive when exposed to UV light in the presence of 1 wt-% Ph3S(CF3SO3) (a known reagent for the photo-generation of acid). In contrast, both A1 and A2 were found to cure well with the VE resin utilizing common free- radical initiators.