Crazing Initiation and Growth in Polymethyl Methacrylate under Effects of Alcohol and Stress

Polymer crazing is typically a precursor to damage and considerably reduces the mechanical performance of polymer materials. The concentrated stress caused by machines and the solvent atmosphere created during machining exacerbates the formation of crazing. In this study, the tensile test method was employed to examine the initiation and progression of crazing. The research focused on polymethyl methacrylate (PMMA), both regular and oriented, and the impact of machining and alcohol solvents on the formation of crazing. The results showed that the alcohol solvent influenced PMMA through physical diffusion, whereas machining primarily affected crazing growth via residual stress. Treatment reduced the crazing stress threshold of PMMA from 20% to 35% and produced a threefold increase in its sensitivity to stress. The findings revealed that oriented PMMA exhibited 20 MPa higher resistance to crazing stress compared with regular PMMA. The results also indicated that the extension of the crazing tip and thickening were in conflict, with the crazing tip of regular PMMA severely bending under tensile stress. This study provides valuable insight into the initiation of crazing and the methods of its prevention.

Automated summary

Polymer crazing is a precursor to damage and significantly reduces the mechanical performance of polymer materials. This study examined the initiation and progression of crazing in PMMA, and the impact of machining and alcohol solvents on its formation. The results showed that alcohol solvents influenced PMMA through physical diffusion, while machining affected crazing growth via residual stress. Treatment reduced the crazing stress threshold and increased sensitivity to stress. Oriented PMMA exhibited higher resistance to crazing stress compared to regular PMMA. This study provides valuable insight into crazing initiation and prevention methods.