Epoxy / Isocyanate System And Its Glass Cloth Composites

Comparing the gel time of resin containing different accelerator (cobalt isocaprylate) content by gel test, it can conclude that the optimum content of accelerator is 0．05%, for CE/EP co-cure system when cure temperature above 180℃. In order to the effect of cyanate ester content, accelerant content, cure time and cure temperature, on heat distorrion temperature(HDT), moisture absorption(M∞), dielectric constant(ε) and dielectric loss tangent(tgδ), the orthogonal table L(4) was used to arrange experiment that containing 16 groups, and measure the HDT, M∞,εand tgδ. Cyanate ester content is the most important factor affecting HDT, M∞,εand tgδby orthogonal theoretic. In addition, it can conclude that the optimal conditions for preparing the sample with the highest DHT is that the blend containing cyanate ester 50% and accelerate 0．05%, cured at 200℃for 3h. The optimal conditions for preparing the sample with the lowest moisture concentration are the blend containing cyanate ester 30% with accelerate 0．20% and cured at 200℃for 3h. The optimal conditions for preparing the sample with the lowestεare the blend containing cyanate ester 50% with accelerate 0．10% and cured at 200℃for 2．5h. The optimal conditions for preparing the sample with the lowestεare the blend containing cyanate ester 50% with accelerate 0．10% and cured at 170℃for 2h. The optimal conditions for preparing the sample with the lowest tgδare the blend containing cyanate ester 50% with accelerate 0．10% and cured at 200℃for 2．5h.Comparing all samples' M∞, the result shows that M∞does not decrease with the cyanate ester content increasing, and not decrease with the cure temperature increasing. HDT increases with the cyanate ester content increasing. After post-cured at 230℃, the value of HDT, M∞and tgδof the samples which contain same cyanate ester content are very close. However, the change ofεis not clearly after post-cured. In addition, FTIR was used to analyze the effect of resin structure on properties.Considering HDT, M∞, cost, workability and some other factors comprehensively, resin containing 40% CE and 0．05% accelerator was used in the experiment for pre-estimating the cure condition of laminated board by DSC. The suitable cure condition is cure at 180℃for 3 hours, and post-cure at 230℃for 2 hours,The real bending modulus (E') and the temperature when E' falling rapidly of composites are connected closely with moisture absorption. When moisture absorption reached saturated, E' and Tg changed little. The value of glass transition temperature (Tg) did not change clearly from the change of loss tangent curves after moisture absorption. However, the height of transition peek changed clearly, and the height of high-temperature transition peek fall with immersion time increased.Comparing static mechanical properties of composites before and after absorb water, shearing strength and bending strength decreased, but Young's modulus did not change largely. Increasing testing temperature, the same conclusion can be get that shearing strength and bending strength decreased, but Young's modulus did not change largely.