Coordinative Chain Transfer Polymerization and Subsequent Sulfur Treatment for Polyolefin Chain Connection via Polysulfide Linkages
- 주제(키워드) Polyolefin , Coordinative Chain Transfer Polymerization , Block copolymers , Inverse vulcanization
- 주제(DDC) 547
- 발행기관 아주대학교 일반대학원
- 지도교수 이분열
- 발행년도 2025
- 학위수여년월 2025. 2
- 학위명 석사
- 학과 및 전공 일반대학원 분자과학기술학과
- 실제URI http://www.dcollection.net/handler/ajou/000000034307
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Coordinative chain transfer polymerization (CCTP) is an advanced technique for synthesizing olefin block copolymers. Despite its innovative nature, CCTP is limited by the molecular weight range it can achieve. This is because chain transfer reactions are hindered when polyolefin chains attached to chain transfer agents (e.g., R2Zn) become too long, a phenomenon linked to the long-chain coiling effect. To address this limitation, this study explores a post-polymerization chain length extension strategy. Specifically, the reaction between (Hexyl)2Zn and S8 yielded CH3(CH2)5- Sa-(CH2)5CH3 (where a = 1–5) with high efficiency. When S8 was added to ethylene/propylene CCTcoP products [(PEP)2Zn] synthesized using Et2Zn, the molecular weight (Mw) increased. However, the increase was not as significant as expected, likely due to the same long-chain coiling effect. On the other hand, CCTcoP products synthesized with (CH2=CHC6H4CH2CH2CH2)2Zn (1) showed Mw increases by 2.8–3.8 times, attributed to additional chain extension facilitated by the reaction of styrene end groups with S8. This methodology enabled the production of diblock copolymers, such as iPP-b-PEP and iPP-b-PE, with Mw values ranging from 80–140 kDa, which could be further extended to 200–400 kDa multi-block copolymers through -Sa- linkages. The high- Mw polymers obtained displayed significantly improved mechanical strength and viscosity. At low frequencies, these materials exhibited pronounced shear thinning behavior compared to conventional CCTP polymers quenched with acids. Keywords Polyolefin, Coordinative Chain Transfer Polymerization, Block copolymers, Inverse vulcanization
more목차
1. Introduction 1
2. Results and Discussion 4
2.1. Dialkylzinc Reactivity with Electrophiles 4
2.2. CCTP using R2Zn (R = Hexyl or Et) and S treatment 7
2.3. CCTP using (CH2=CHC6H4CH2CH2CH2)2Zn and S treatment 10
2.4. Synthesis of block copolymers 16
2.5. Rheological properties 22
2.6. Tensile properties 26
3. Conclusion 27
4. Experimental Section 28
4.1. General remarks 28
4.2. Reaction of (Hexyl)2Zn with S 29
4.3. Synthesis of iPP-b-PEP (entry 2 in Table 2) 30
5. Reference 32
6. Supporting information 38
