A New Semicrystalline Polymer from Renewable Source: Poly-1,4-(3-methylene-cyclopentene) as an Example of Three-Dimensional Topotactic Transition Triggered by Temperature,Macromolecules

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A New Semicrystalline Polymer from Renewable Source: Poly-1,4-(3-methylene-cyclopentene) as an Example of Three-Dimensional Topotactic Transition Triggered by Temperature
Macromolecules ( IF 5.1 ) Pub Date : 2024-07-24 , DOI: 10.1021/acs.macromol.4c01563
Claudia Napolitano ₁ , Veronica Paradiso ₂ , Marco Naddeo ₂ , David Hermann Lamparelli ₂ , Fabia Grisi ₂ , Odda Ruiz de Ballesteros ₁ , Giuseppe Femina ₁ , Carmine Capacchione ₂ , Finizia Auriemma ₁

Affiliation

In search for biobased alternatives to fossil-based polymers, a synthetic approach is developed that allows the polymerization of a terpene-derived monomer, 3-methylene-cyclopentene (MCP), to poly-1,4-MCP (pMCP) with a high yield and elevated molecular mass. The so-obtained pMCP is regioregular, has an endocyclic double bond/monomer in a fixed cis configuration, and is characterized by random enchainment of monomers with the tertiary C atom in R and S configurations. Yet, it crystallizes from the melt with chains in a nearly extended conformation (average chain periodicity c ≈ 0.96 nm) in the monoclinic system. Upon heating, the low-temperature crystalline (LTC) form transforms, before melting, in a disordered, high-temperature crystalline form (HTC), characterized by the same extended conformation of the LTC form, and orthorhombic crystals of larger apparent coherence length, through a three-dimensional topotactic transition. This transition entails that close neighboring coherence domains of the LTC form rearrange themselves, forming domains of large size not only along the lattice directions of the unit cell perpendicular to the chain axes but also parallel to the chain axes. This unique temperature-driven LTC → HTC topotactic transition is reversible and, upon cooling, the large HTC domains break, forming smaller domains of the LTC form.

中文翻译：

来自可再生来源的新型半晶聚合物：聚 1,4-(3-亚甲基-环戊烯) 作为温度触发的三维拓扑转变的例子

为了寻找化石聚合物的生物基替代品，开发了一种合成方法，可以将萜烯衍生单体 3-亚甲基环戊烯 (MCP) 聚合成聚 1,4-MCP (pMCP)，且具有高聚合度产率和提高的分子量。如此获得的pMCP是区域规则性的，具有固定顺式构型的环内双键/单体，并且其特征在于具有R和S构型的叔C原子的单体的随机链结。然而，它从熔体中结晶出来，其链在单斜晶系中几乎延伸的构象（平均链周期c ≈ 0.96 nm）。加热后，低温结晶（LTC）形式在熔化之前转变为无序的高温结晶形式（HTC），其特征在于与 LTC 形式相同的扩展构象，以及具有较大表观相干长度的斜方晶体，通过三维拓扑转变。这种转变需要 LTC 的紧密相邻的相干域自行重新排列，不仅沿着垂直于链轴的晶胞晶格方向，而且平行于链轴形成大尺寸的域。这种独特的温度驱动的 LTC → HTC 拓扑转变是可逆的，并且在冷却时，大的 HTC 域破裂，形成 LTC 形式的较小域。

更新日期：2024-07-24

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