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以基于Cr系催化剂、不同己烯含量的管材用乙烯己烯共聚物为研究对象,应用~1H固体NMR技术测定了其室温下的相结构参数以及不同温度下的相结构变化。研究发现,随着共聚单体含量的增加,NMR结晶相组分的含量降低,界面区和无定形区组分含量增加,且两者在NMR测定的长周期中所占的比例也增加。提出了以界面区含量和无定形区含量的比例随温度的变化作为定性判断非晶区中链段运动受限程度的依据。此外,采用相同的~1H固体NMR技术研究了不同耐压等级聚乙烯管材料基体树脂的聚集态结构。发现室温下随着管材料耐压等级的增加,结晶相组分含量减少而其他两组分含量增加,且NMR测定的长周期中结晶相组分所占比例降低而其他两组分比例升高。实验结果证明,上述定性判断非晶区中链段运动受限程度的判据与材料的耐压等级有较好的对应关系。
The ethylene-hexene copolymer based on Cr-based catalysts and different hexene contents was used as the research object. The phase structure parameters at room temperature and the phase structure changes at different temperatures were measured by ~ 1H solid state NMR. The results show that with the increase of comonomer content, the content of NMR crystalline phase components decreases, the content of interfacial and amorphous regions increases, and the proportion of the two components in the long period of NMR measurement also increases. It is proposed that the change of the ratio of the content of the interface zone and the content of the amorphous zone with the temperature as a criterion for judging the extent of the segment movement in the amorphous region qualitatively. In addition, the same ~ 1H solid state NMR technique was used to study the aggregated structure of matrix resin with different pressure levels. It is found that the content of the crystalline phase component decreases while the content of the other two components increases at room temperature with the increase of the withstand voltage of the tube material. The proportion of the crystalline phase component in the long period determined by NMR decreases and the proportions of the other two components increase . The experimental results show that the criteria for determining the degree of motion of the segment in the amorphous region qualitatively have a good correspondence with the withstand voltage of the material.