Test methods including OM, SEM, TEM, DSC, SAXS, WAXS, and IR were used to characterise supra-molecular structure in three batches of polyethylene (PE), which had weight-average relative molar masses ${\overline{M}}_{\text{w}}$of approximately 0.6 × 10⁶, 5 × 10⁶, and 9 × 10⁶. They were applied to compression mouldings made by the polymer manufacturer. Electron microscopy showed that powders formed in the polymerization reactor consisted of irregularly shaped grains between 50 and 250 μm in diameter. Higher magnification revealed that each grain was an aggregate, composed of particles between 0.4 and 0.8 μm in diameter, which were connected by long, thin fibrils. In compression mouldings, lamellar thicknesses ranged from 7 to 23 nm. Crystallinity varied between 70 and 75 % in reactor powder, but was lower in compression mouldings. Melting peak temperatures ranged from 138 to 145 °C, depending on processing history. DMTA showed that the glass transition temperature θ_g was −120 °C for all three grades of polyethylene. IR spectroscopy found negligibly small levels of oxidation and thermal degradation in mouldings. Optical microscopy revealed the presence of visible fusion defects at grain boundaries. It is concluded that relatively weak defects can be characterized using optical microscopy, but there is a need for improved methods that can detect less obvious fusion defects.

中文翻译：

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超高分子量聚乙烯的结构，加工和性能（IUPAC技术报告）。第2部分：结晶度和超分子结构

使用包括OM，SEM，TEM，DSC，SAXS，WAXS和IR在内的测试方法来表征三批具有重均相对摩尔质量的聚乙烯（PE）的超分子结构 ${\overline{\mathrm{中号}}}_{\text{w}}$的大约0.6×10 ⁶，5×10 ⁶，和9×10 ⁶。它们被应用于由聚合物制造商制造的压模。电子显微镜显示，在聚合反应器中形成的粉末由直径在50至250μm之间的不规则形状的晶粒组成。更高的放大倍数表明，每个晶粒都是聚集体，由直径在0.4到0.8μm之间的颗粒组成，这些颗粒由长而细的原纤维连接。在压模中，层状厚度为7至23 nm。反应器粉末的结晶度在70％到75％之间变化，但在压模中较低。熔融峰值温度范围为138至145°C，具体取决于处理历史。DMTA表明玻璃化转变温度θ对于所有三个等级的聚乙烯，_g均为-120℃。红外光谱发现模制品中少量的氧化和热降解。光学显微镜显示在晶界处存在可见的熔合缺陷。结论是，可以使用光学显微镜表征相对较弱的缺陷，但是需要能够检测到不太明显的融合缺陷的改进方法。