Multivariable dependency of thermal shrinkage in highly aligned polypropylene tapes for self-reinforced polymer composites

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• 作者：Jairo A. Diaz ^{jdiazama@purdue.edu" class="auth_mail" title="E-mail the corresponding author} ; Jeffrey P. Youngblood ; ^{jpyoungb@purdue.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：A. Self-reinforced composite ; B. Thermal properties ; C. Analytical modeling ; D. Thermal shrinkage
• 刊名：Composites Part A: Applied Science and Manufacturing
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：90
• 期：Complete
• 页码：771-777
• 全文大小：1684 K

文摘

Self-reinforced composites offer a unique combination of properties such as high specific strength, high impact resistance, and recyclability by incorporating highly aligned fibers within a random matrix of the same polymer. However, high temperatures will shrink the system to recover randomness in the aligned segments, compromising the composite thermal stability during processing as self-reinforced tapes are consolidated into the final composite through heating and pressure. Hence, the dynamic nonlinear multivariable (i.e., time, temperature, stress) shrinkage exhibited by self-reinforced polypropylene (SRPP) tapes was measured and modeled at the maximum shrinkage limit achieved in the proximity of the composite processing temperature [∼140 to160 °C]. At high stress (∼7.5 MPa) the thermal shrinkage of the SRPP tapes was reduced and a parallel creep mechanism was activated. The modeling, and prediction of the main factors governing the thermal shrinkage expand and diversify the dynamic design window for new SRPP composites.