Mechanical degradation of polymers reported so far, utilize cutting, impact or attrition for size reduction, which is very different from the low-magnitude forces experienced by the polymers during their service life. In this work, we have studied the effect of such low-magnitude forces, on the polymeric materials, using a low-energy rolling compression-type wet-grinder. The rolling compression action produces shear and compression on the polymer, leading to abrasion and resulting in the formation of crazes, micro-cracks and chip-offs, akin to the wearing. Measurements using Raman spectroscopy showed that the shear forces, generated upon grinding, produced strains on the polymer backbone, which upon sufficient build-up, results in chain scission at the points of physical entanglement. These homolytic chain scissions produced "mechano"radicals, which were confirmed by radical-scavenging using DPPH. The ensuing reduction in the molecular weight was further analyzed using GPC, light scattering and viscometry. Surprisingly, XRD measurements showed strain-induced crystallization as well. In order to theoretically validate the studies, a probabilistic model, explaining the "complex" response of the molecular weight distribution and the PDI upon mechanical degradation, has also been presented. Crosslink density function was incorporated to explain the preferential chain scission of the high molecular weight species, leading to a gradual reduction in the average molar mass.

迄今为止报道的聚合物的机械降解利用切割，冲击或磨损来减小尺寸，这与聚合物在使用寿命期间所经历的低强度力有很大不同。在这项工作中，我们使用低能滚动压缩式湿式研磨机研究了这种低幅值力对聚合物材料的影响。滚动压缩作用在聚合物上产生剪切和压缩，导致磨损，并导致形成类似于磨损的裂纹，微裂纹和碎屑。使用拉曼光谱法的测量表明，在研磨时产生的剪切力在聚合物主链上产生了应变，该应变在充分积累时会导致在物理缠结点处发生断链。这些均裂链断裂产生“机械” 自由基，通过使用DPPH清除自由基进行确认。使用GPC，光散射和粘度测定法进一步分析了随之而来的分子量降低。出乎意料的是，XRD测量也显示出应变诱导的结晶。为了从理论上验证研究，还提出了一个概率模型，该模型解释了分子量分布和PDI在机械降解后的“复杂”响应。交联密度函数被并入以解释高分子量物质的优先断链，导致平均摩尔质量的逐渐降低。XRD测量也显示出应变诱导的结晶。为了从理论上验证研究，还提出了一个概率模型，该模型解释了分子量分布和PDI在机械降解后的“复杂”响应。交联密度函数被并入以解释高分子量物质的优先断链，导致平均摩尔质量的逐渐降低。XRD测量也显示出应变诱导的结晶。为了从理论上验证研究，还提出了一个概率模型，该模型解释了分子量分布和PDI在机械降解后的“复杂”响应。交联密度函数被并入以解释高分子量物质的优先断链，导致平均摩尔质量的逐渐降低。