测定了有机玻璃的抗裂纹增长因子K_(1C)与材料组份、拉力机夹头速度的关系。发现增塑剂和交联剂对抗裂纹性能的影响,可从聚合物分子运动能力对裂纹端点塑性屈服过程的影响说明。在对断面形态、断面层厚度、折光指数以及K_(1C)值与拉力机夹头速度关系研究之后,认为用“撕布”模式和次级断裂模式分别解释慢裂纹、快裂纹扩展过程中的实验现象是合适的。 The relationship between anti-crack growth factor K_ (1C) and material composition and tensile chuck speed of plexiglass was measured. The effects of plasticizers and crosslinkers on the crack resistance were investigated. The effects of plasticity of polymer molecules on the plastic yield process at the crack tip were investigated. After studying the relationship between section shape, section thickness, refractive index and K1C value and chuck speed, it is considered that “slow tear” mode and secondary break mode are used to explain the influence of slow crack and rapid crack propagation The experimental phenomenon is suitable.