中文摘要
在超临界CO2 中增加压力和延长时间均有助于iPB-1 从晶型2 向晶型1 的转变；在室温下长时间放置转变得到的是孪生六方结构（晶形I ），而在超临界CO2 中处理得到的却是非孪生六方结构（ 晶型I' ）；富含丁烯的sPPBU共聚物单晶呈现长方形或板条状，其长轴沿着结晶学的b轴方向。丙烯单体的引入对于sPB的结晶行为影响很大。随着丙烯单元含量的增加，共聚物单晶的长宽比增大，得到的共聚物单晶类似于sPP均聚物的单晶。电子衍射结果表明直到丙烯单元含量达到9.1mol%时，其对于sPP链堆积的影响才表现出来； 含少量1-丁烯单元的丙稀-1丁烯无规共聚物能够在一个较宽的温度范围内形成α-iPP和γ-iPP的混合晶体，并且γ-iPP晶体含量在130 C达到最大。另外，α-iPP和γ-iPP晶体几乎是同时生成的，而且在结晶过程中γ-iPP在整个晶体中的含量保持在25％左右。对于丙稀-1丁烯无规共聚物形成的α-iPP和γ-iPP的混合晶体也无法在形态上将它们区分开,因为它们在同一个球晶中混合出现。
英文摘要
Both increasing press and time can accelerate the transformation from Form II to Form I of iPB in supercritical CO2. Instead of the double, twined hexagonal pattern of transformed form I, the six point patterns are preferred when the form II iPB-1 samples are treated in supercritical CO2. Single crystals of syndiotactic poly(propene-co-1-butene) (sPPBU) copolymers with 1-butene as the rich component exhibit rectangular or lath-like shapes with their long axes along their crystallographic b-axis. Incorporating propene units in the sPB-1 chains influences the crystallization behavior of the sPB-1 significantly. The aspect ratio of the single crystals increases with increasing the propene units, resulting in copolymer single crystals more similar to those of the sPP homopolymer. The electron diffraction results indicate that a small amount of propene units, up to 9.1 mol%, shows no detectable effect on the C-centered chain packing of form I of sPB-1. both the α and γ modifications can be formed in the random propylene-based copolymer containing a little 1-butene as co-unit in a wide temperature range.The γ-iPP content in the copolymer reaches maximum at the temperature of 130 C and it takes always ca. 25% of the overall crystallinity. This leads to the conclusion that α- and γ-iPP crystals grow simultaneously during the crystallization process. The fact that the α and γ phases cannot be distinguished by morphological observation leads to the conclusion that they may intermix within one spherulite.
结题摘要
在超临界CO2 中增加压力和延长时间均有助于iPB-1 从晶型2 向晶型1 的转变；在室温下长时间放置转变得到的是孪生六方结构（晶形I ），而在超临界CO2 中处理得到的却是非孪生六方结构（ 晶型I' ）；富含丁烯的sPPBU共聚物单晶呈现长方形或板条状，其长轴沿着结晶学的b轴方向。丙烯单体的引入对于sPB的结晶行为影响很大。随着丙烯单元含量的增加，共聚物单晶的长宽比增大，得到的共聚物单晶类似于sPP均聚物的单晶。电子衍射结果表明直到丙烯单元含量达到9.1mol%时，其对于sPP链堆积的影响才表现出来； 含少量1-丁烯单元的丙稀-1丁烯无规共聚物能够在一个较宽的温度范围内形成α-iPP和γ-iPP的混合晶体，并且γ-iPP晶体含量在130 C达到最大。另外，α-iPP和γ-iPP晶体几乎是同时生成的，而且在结晶过程中γ-iPP在整个晶体中的含量保持在25％左右。对于丙稀-1丁烯无规共聚物形成的α-iPP和γ-iPP的混合晶体也无法在形态上将它们区分开,因为它们在同一个球晶中混合出现。