Abstract The shear-induced crystallization of bimodal polyethylene with high molecular weight fraction having different content of short chain branch at low shear rate and high temperatures was investigated by in-situ small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) techniques. SAXS and WAXD results indicate that shish crystals form at different shear temperatures of 139 and 136 °C, subsequently kebab crystals and oriented lamellae form at the isothermal crystallization temperature of 121 °C. The presence of short chain branch significantly promotes the formation of shish-kebab crystals owing to the increase of the relaxation time, but overmuch short chain branch impedes the formation of shish-kebab crystals and form more oriented lamellae. These evidences clearly indicate that even though the existence of short chain branch impedes the crystallizability, it can still effectively promote the formation of shish-kebab crystals at high shear temperatures.

中文翻译：

---

短链支化对高剪切温度下双峰聚乙烯剪切诱导晶体形成的影响

摘要 采用原位小角 X 射线散射 (SAXS) 和广角 X-射线散射法研究了短链支化含量不同的高分子量双峰聚乙烯在低剪切速率和高温下的剪切诱导结晶。射线衍射 (WAXD) 技术。SAXS 和 WAXD 结果表明，shish 晶体在 139 和 136 °C 的不同剪切温度下形成，随后在 121 °C 的等温结晶温度下形成烤肉串晶体和定向薄片。由于弛豫时间的增加，短支链的存在显着促进了烤羊肉串晶体的形成，但过多的短支链阻碍了烤羊肉串晶体的形成并形成了更多取向的薄片。