Microstructure evolution of poly[tetrafluoroethylene-co-(perfluoropropylvinylether)] films under uniaxial deformation

POLYMER

卷:99

Article

Yin, Chaoqing^1,2,3  Miranda, Daniel F.¹  Zhang, Shihai⁴  Zhang, Qinghua³  Runt, James¹ 

[1] Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16802 USA

[2] Kingfa Sci & Technol Co LTD, Natl Certified Enterprise Technol Ctr, Guangzhou, Guangdong, Peoples R China

[3] Donghua Univ, Coll Mat Sci & Engn, State Key Lab Modificat Chem Fibers & Polymer Mat, Shanghai 201620, Peoples R China

[4] PolyK Technol LLC, 2124 Old Gatesburg Rd, State Coll, PA 16803 USA

关键词: Polymer morphology;    Uniaxial drawing;    Crystalline polymers;    Polymer dynamics;   

DOI  :  10.1016/j.polymer.2016.07.044

来源: Elsevier

【 摘 要 】

This paper presents an investigation of semi-crystalline poly[tetrafluoroethylene -co-(perfluoropropylvinylether)] (PFA) films uniaxially drawn at two temperatures. The extent of crystal unit cell orientation increased significantly with drawing at both draw temperatures as expected, but crystallinity was found to increase with draw ratio only at the lower draw temperature, remaining unchanged at the higher temperature. Considering the evolution of small-angle X-ray scattering patterns as a function of deformation, a model for the changes in PFA lamellar microstructure on drawing was developed. The observed mechanical alpha and gamma relaxations of PFA were assigned to relaxation of rigid and mobile amorphous segments, respectively. Drawing at 200 degrees C to a draw ratio of 7 leads to a similar to 40 degrees C increase in the alpha transition temperature compared to the unoriented film, and the findings support the key role of molecular orientation in suppressing the cooperative motions of non-crystalline segments in drawn polymers. (C) 2016 Elsevier Ltd. All rights reserved.

【 授权许可】

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