Phase relations in poly(vinyl chloride)/ethylene‐‐vinyl acetate copolymer blends with low contents of the EVA polymer
Phase relations in poly(vinyl chloride)/ethylene‐‐vinyl acetate copolymer blends with low contents of the EVA polymer
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DOI：
10.1002/app.1977.070210407
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发表时间：
1977-04
影响因子：
3
通讯作者：
S. Svanson;C. Elmqvist;Y. Shur;B. Rånby
中科院分区：
文献类型：
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作者：
S. Svanson;C. Elmqvist;Y. Shur;B. Rånby
通过在室温(0)下混合，在160°C下研磨15分钟(I)，然后在170°C下热处理20分钟（II）和40分钟（III），制备了一系列由商用聚氯乙烯（悬浮液-聚合粉末）和乙烯-醋酸乙烯共聚物（EVA, 45 wt % VA）（含2-10 wt % EVA）组成的聚合物共混物。质子在室温下的宽线核磁共振测量显示一个宽频带（分配给PVC相）和一个叠加的窄带（分配给移动EVA相）。0个样品的频带强度较窄，对应于总EVA含量；i -样品的窄带强度低于预期，表明2-3%的EVA包含在刚性PVC相中。热处理20 min （II）和40 min （III）后，除含2 wt % EVA的共混物不存在可分离的窄带外，其余样品的窄带强度均向0相分离方向增加。这些结果表明，约2 wt %的EVA与PVC相相容且处于平衡状态，而超过2 wt % EVA的共混物则是亚稳态的。
A series of polymer blends of commercial poly(vinyl chloride) (suspension-polymerized powder) and an ethylene–vinyl acetate copolymer (EVA with 45 wt % VA) containing 2–10 wt % EVA were prepared by mixing at room temperature (0) and by milling at 160°C for 15 min (I) and then heat treated at 170°C for 20 min (II) and 40 min (III). Wide-line NMR measurements for protons at room temperature show a broad band (assigned to PVC phase) and a superimposed narrow band (assigned to mobile EVA phase). The 0-samples had a narrow band intensity corresponding to the total EVA content; the I-samples had a less intense narrow band than expected, indicating that 2–3% EVA was included in the rigid PVC phase. Heat treatment for 20 min (II) and 40 min (III) increased the narrow band intensity toward the 0-samples showing phase separation except for milled blends containing 2 wt % EVA, which had no separable narrow band and remained so. These results indicate that about 2 wt % EVA is compatible with the PVC phase and in equilibrium, while milled blends with more than 2 wt % EVA are metastable.