半二茂钛催化剂合成含环戊烷/环己烷单元的乙烯/异戊二烯共聚物作为独特的弹性体,Macromolecules

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半二茂钛催化剂合成含环戊烷/环己烷单元的乙烯/异戊二烯共聚物作为独特的弹性体
Macromolecules ( IF 5.1 ) Pub Date : 2023-01-19 , DOI: 10.1021/acs.macromol.2c02399
Lijuan Guo ₁ , Ryoji Makino ₁ , Daisuke Shimoyama ₁ , Joji Kadota ₂ , Hiroshi Hirano ₂ , Kotohiro Nomura ₁

Affiliation

乙烯 (E) 与异戊二烯 (IP) 的共聚物具有比报道的催化剂制备的那些（T _g低于 -18 °C）更高的玻璃化转变温度（T _g值，-7.1 至 29.2 °C）已在共聚反应中制备使用含有酚盐配体的半二茂钛催化剂，Cp'TiCl ₂ (O-2,6- ⁱ Pr ₂ -4-RC ₆ H ₂ ) [Cp' = C ₅ Me ₅ (Cp*), R = H ( 1 ), SiEt ₃ ( 2)]。他们通过 NMR 光谱进行的微观结构分析表明，除了 1,4- 和 3,4-IP 插入单元作为主要单元观察到的外，共聚物还含有环戊烷（主要）和环己烷单元，这些单元是在 IP 和随后的乙烯插入后通过环化形成的由报道的催化剂制备。1,2,4-Me ₃ C ₅ H _{2类似物 (R = H) 表现出更好的 IP 掺入，但}_由于较少的环戊烷单元，所得 E/IP 共聚物与 1、2 制备的那些相比具有相当低的Tg值在微观结构中。Tg _ _{_}E/IP 共聚物中的值随着 IP 含量的增加而增加，并且程度取决于所使用的催化剂。由于其独特的微观结构，由1 , 2 –MAO 催化剂体系制备的 E/IP 共聚物表现出良好的拉伸和弹性性能。拉伸强度最初随着 IP 含量的增加以及断裂伸长率的增加而降低（高达 600%，IP 3.3-15.6 mol %），然后随着 IP 含量的进一步增加逐渐增加（IP 18.1-21.5摩尔％）；然后断裂伸长率随着保持拉伸强度以及屈服应力的观察而降低。

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Synthesis of Ethylene/Isoprene Copolymers Containing Cyclopentane/Cyclohexane Units as Unique Elastomers by Half-Titanocene Catalysts

Ethylene (E) copolymers with isoprene (IP) possessing higher glass-transition temperatures (T_g values, −7.1 to 29.2 °C) than those prepared by the reported catalysts (T_g below −18 °C) have been prepared in the copolymerization by using half-titanocene catalysts containing phenoxide ligand, Cp′TiCl₂(O-2,6-ⁱPr₂-4-R-C₆H₂) [Cp′ = C₅Me₅ (Cp*), R = H (1), SiEt₃ (2)]. Their microstructural analysis by NMR spectra revealed that the copolymers contained cyclopentane (major) and cyclohexane units, formed by cyclization after IP and subsequent ethylene insertions, in addition to 1,4- and 3,4-IP inserted units observed as major units in those prepared by reported catalysts. The 1,2,4-Me₃C₅H₂ analogue (R = H) showed better IP incorporation, but the resulting E/IP copolymers possessed rather low T_g values compared to those prepared by 1,2 due to less cyclopentane unit in the microstructure. The T_g value in the E/IP copolymer increased upon the increase of the IP content, and the degree was dependent upon the catalyst employed. Due to their unique microstructure, the resulting E/IP copolymers prepared by 1,2–MAO catalyst systems exhibit promising tensile and elastic properties. The tensile strength initially decreased with an increase in the IP content along with an increase of the elongation at break (up to 600%, IP 3.3–15.6 mol %) and then increased gradually with further increase in the IP contents (IP 18.1–21.5 mol %); the elongation at break then decreased with preserving the tensile strength along with the observation of the yield stress.

更新日期：2023-01-19

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