1
|
Liao Y, Pérez-Camargo RA, Sardon H, Martínez de Ilarduya A, Hu W, Liu G, Wang D, Müller AJ. Challenging Isodimorphism Concepts: Formation of Three Crystalline Phases in Poly(hexamethylene- ran-octamethylene carbonate) Copolymers. Macromolecules 2023; 56:8199-8213. [PMID: 37900097 PMCID: PMC10601535 DOI: 10.1021/acs.macromol.3c01265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 09/01/2023] [Indexed: 10/31/2023]
Abstract
In this work, poly(hexamethylene-ran-octamethylene carbonate) copolycarbonates were synthesized by melt polycondensation in a wide range of compositions. The copolymers displayed some of the characteristic isodimorphic thermal behavior, such as crystallization for all the compositions and a pseudoeutectic behavior of the melting temperature (Tm) versus composition. The pseudoeutectic point was located at 33 mol % poly(octamethylene carbonate) (POC) content (i.e., corresponding to the PH67O33C copolymer). Surprisingly, the crystallinities (Xc) for a wide range of copolymer compositions were higher than those of the parent components, a phenomenon that has not been observed before in isodimorphic random copolymers. The structural characterization, performed by wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering experiments, revealed unexpected results depending on composition. On the one hand, the poly(hexamethylene carbonate) (PHC)- and POC-rich copolymers crystallize in PHC- and POC-type crystals, as expected. Moreover, upon cooling and heating, in situ WAXS experiments evidenced that these materials undergo reversible solid-solid transitions [δ-α (PHC) and δ-α-β (POC)] present in the parent components but at lower temperatures. On the other hand, a novel behavior was found for copolymers with 33-73 mol % POC (including the pseudoeutectic point), which are those with higher crystallinities than the parent components. For these copolymers, a new crystalline phase that is different from that of both homopolymers was observed. The in situ WAXS results for these copolymers confirmed that this novel phase is stable upon cooling and heating and does not show any crystallographic feature of the parent components or their solid-solid transitions. FTIR experiments confirmed this behavior, revealing that the new phase adopts a polyethylene-like chain conformation that differs from the trans-dominant ones exhibited by the parent components. This finding challenges the established concepts of isodimorphism and questions whether a combination of crystallization modes (isodimorphism and isomorphism) is possible in the same family of random copolymers just by changing the composition.
Collapse
Affiliation(s)
- Yilong Liao
- POLYMAT
and Department of Polymers and Advanced Materials: Physics, Chemistry,
and Technology, Faculty of Chemistry, University
of the Basque Country UPV/EHU, Paseo Manuel de Lardizábal, 3, Donostia-San Sebastián 20018, Spain
| | - Ricardo A. Pérez-Camargo
- POLYMAT
and Department of Polymers and Advanced Materials: Physics, Chemistry,
and Technology, Faculty of Chemistry, University
of the Basque Country UPV/EHU, Paseo Manuel de Lardizábal, 3, Donostia-San Sebastián 20018, Spain
| | - Haritz Sardon
- POLYMAT
and Department of Polymers and Advanced Materials: Physics, Chemistry,
and Technology, Faculty of Chemistry, University
of the Basque Country UPV/EHU, Paseo Manuel de Lardizábal, 3, Donostia-San Sebastián 20018, Spain
| | - Antxon Martínez de Ilarduya
- Department
of Chemical Engineering, Polytechnic University
of Catalonia ETSEIB-UPC, Diagonal 647, Barcelona 08028, Spain
| | - Wenxian Hu
- Beijing
National Laboratory for Molecular Sciences, CAS Key Laboratory of
Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
- University
of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Guoming Liu
- Beijing
National Laboratory for Molecular Sciences, CAS Key Laboratory of
Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
- University
of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Dujin Wang
- Beijing
National Laboratory for Molecular Sciences, CAS Key Laboratory of
Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
- University
of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Alejandro J. Müller
- POLYMAT
and Department of Polymers and Advanced Materials: Physics, Chemistry,
and Technology, Faculty of Chemistry, University
of the Basque Country UPV/EHU, Paseo Manuel de Lardizábal, 3, Donostia-San Sebastián 20018, Spain
- Ikerbasque,
Basque Foundation for Science, Plaza Euskadi 5, Bilbao 48009, Spain
| |
Collapse
|
3
|
Zhao XT, Men YF. Thermal Fractionation of Polyolefins: Brief History, New Developments and Future Perspective. POLYMER SCIENCE SERIES A 2022. [DOI: 10.1134/s0965545x22700419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Abstract
For semi-crystalline polymer materials, the difference in chain structure often leads to different physical properties; therefore, in-depth analysis of the chain structure is of great significance. With the continuous development of advanced instruments, many research means have emerged to characterize the structure of molecular chains. Among them, fractionation techniques provide effectively structural information on inter- and intra-molecular comonomer distribution, branching degree, and sequence length, etc. This work briefly presents the history of developments of various classical fractionation means such as temperature-rising elution fractionation, stepwise crystallization and successive self-nucleation and annealing, while focusing on the present and future of their applications.
Collapse
|