Zhou Ye, Liu Wenting, Tan Bin, Zhu Cheng, Ni Yaru, Fang Liang, Lu Chunhua, Xu Zhongzi
State Key Laboratory of Materials-Oriented Chemical Engineering, College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009, China.
Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Nanjing Tech University, Nanjing 210009, China.
Polymers (Basel). 2021 Mar 24;13(7):998. doi: 10.3390/polym13070998.
Polyvinylidene fluoride (PVDF) and poly(methyl methacrylate) (PMMA) blend films were prepared using biaxial stretching. The effects of PMMA content and stretching ratio on the crystallinity and β phase fraction of PVDF in blend films were investigated. The distributions of crystallinity and β phase fraction on variable locations were also studied. The results of FTIR and XRD showed that β phase appeared in PVDF/PMMA blends after extrusion and casting procedures. Although β phase fraction decreased after preheating, there was still an increasing trend during following biaxial stretching. More importantly, the increase in PMMA content improved β phase fraction, and the highest β phase fraction of 93% was achieved at PMMA content of 30 wt% and stretching ratio of 2×2. Besides, the reduction in PMMA content and the increase in stretching ratio improved the crystallinity of PVDF. The mechanical properties of the stretched films were significantly improved by increasing the stretching ratio as well. The uniform stress distribution on different regions of biaxial stretching films contributed to the uniform distribution of β phase fraction and crystallinity of PVDF with the aid of simulation. This work confirmed that biaxial stretching can be a candidate method to prepare PVDF/PMMA blend films with uniform distributions of comparable β phase and crystallinity of PVDF.
采用双轴拉伸法制备了聚偏氟乙烯（PVDF）与聚甲基丙烯酸甲酯（PMMA）共混薄膜。研究了PMMA含量和拉伸比 对共混薄膜中PVDF结晶度和β相含量的影响。还研究了结晶度和β相含量在不同位置的分布情况。傅里叶变换红外光谱（FTIR）和X射线衍射（XRD）结果表明，在挤出和流延工艺后，PVDF/PMMA共混物中出现了β相。尽管预热后β相含量有所降低，但在随后的双轴拉伸过程中仍呈上升趋势。更重要的是，PMMA含量的增加提高了β相含量，在PMMA含量为30 wt%、拉伸比为2×2时，β相含量最高达到93%。此外，PMMA含量的降低和拉伸比的增加提高了PVDF的结晶度。拉伸比的增加也显著改善了拉伸薄膜的力学性能。借助模拟，双轴拉伸薄膜不同区域的均匀应力分布有助于PVDF的β相含量和结晶度的均匀分布。这项工作证实，双轴拉伸可以作为一种制备具有可比β相和PVDF结晶度均匀分布的PVDF/PMMA共混薄膜的候选方法。
