固化度和玻璃化转变玻璃化转变温度如何随着固化度变化.PPT

* * DMA: 涂料和粘结剂 弯曲和拉伸模式主要是测量基体材料的行为： 不适合测试附着在坚硬的基体材料上的薄涂层，拉伸模式可能导致薄涂层的剥离.。 样品有破碎的可能，很难夹持住脆性样品。 压缩模式: 样品通常非常坚硬很难压缩。 剪切模式是最好的测试方法. 对于基体上附着的薄涂层样品有极高的灵敏度。 * Coating material DMA: 涂料和粘结剂 * DMA: 涂料和粘结剂 * DMA: 预浸渍 谢谢 * * Questions cover many products. What if no thermosets would be available? Questions over the whole life of such a material. * * Araldit is an epoxy resin used in this case as hous hold adhesive. The DSC curves show the fresh resin with low Tg and full reaction peak; partially cured with increased Tg and smaller peak; fully cured with Tg above 100°C and no peak The results are not shown in the next slide!!!!!!!!!!! * The measurement points are from an other resin. To show the principle See an other curve Tg versus conversion in Figure 7 in the UserCom 11 Chapter on the Glass transiton, curing behavior. And the References: 1. Addition of a reactive diluent to a catalyzed epoxy-anhydride system. I. Influence on the cure kinetics. S.Montserrat, G. Andreu, P. Cortés, Y. Calventus, P. Colomer, J.M. Hutchinson and J. Málek Journal of Applied Polymer Science, Vol. 61, 1663 (1996) 2. Vitrification and further structural relaxation in the isothermal curing of an epoxy resin S.Montserrat Journal of Applied Polymer Science, Vol. 44, 545 (1992) * Brochure on TA competence, Thermosets Chapter 2.1.3 DMP 30 (picture) is an other accelerator * Often, fast curing produces less dense network which shows lower glass transition. Reasion is the loss of mobility of reactive groups. Tg2: at about 120°C (small step). Phase separation: Reaction creates two networks with different Tg‘s * Vol 2 p.88 * Isothermal curing is a possibility. The higher the temperature the lower the curing time. The limit is the decomposition temperature. For a fully cured material, the isothermal curing temperature must be: Tiso Tgfully_cured The basic powder material was heated up to 150 °C and kept isothermally for a defined time. Afterwards these different cured materials were measured again.