Qi Xin, Xie Fei, Zhang Jichuan, Zhang Liqun, Yue Dongmei
State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology Beijing 100029 PR China
Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials Beijing 100029 PR China.
RSC Adv. 2019 Dec 20;9(72):42367-42374. doi: 10.1039/c9ra07856h. eCollection 2019 Dec 18.
gum (EUG) is an important bio-based material with a structure similar to that of natural rubber. However, EUG is a hard plastic at room temperature due to crystallization, which limits its wide application. In this paper, a bio-based cyclized gum (CEUG) elastomer with various degrees of cyclization was prepared using TiCl/CHCOOH as catalysts. H-NMR and FT-IR techniques were used to obtain structure information. It was found that di-, tri-, and tetra-substituted olefins in the cyclized sequence were formed during cyclization. DSC and XRD results indicated that the cyclized structure could inhibit crystallization. When the degree of cyclization reached 8.2%, crystallization disappeared and the material transformed from a plastic into an elastomer. With increasing of the degree of cyclization, the glass transition temperature ( ) of CEUG increased and the thermal stability was enhanced, but the molecular weight decreased significantly. Above all, DMA results showed that the tan could reach 1.2 when the degree of cyclization was 20.0%, and the damping temperature range could be adjusted by controlling the degree of cyclization. This new elastomer is expected to contribute to the development of damping materials.
杜仲胶（EUG）是一种重要的生物基材料，其结构与天然橡胶相似。然而，由于结晶作用，杜仲胶在室温下是一种硬塑料，这限制了它的广泛应用。本文以TiCl/CHCOOH为催化剂制备了具有不同环化度的生物基环化杜仲胶（CEUG）弹性体。采用H-NMR和FT-IR技术获取结构信息。研究发现，环化过程中形成了环化序列中的二取代、三取代和四取代烯烃。DSC和XRD结果表明，环化结构可以抑制结晶。当环化度达到8.2%时，结晶消失，材料从塑料转变为弹性体。随着环化度的增加，CEUG的玻璃化转变温度（ ）升高，热稳定性增强，但分子量显著降低。最重要的是，DMA结果表明，当环化度为20.0%时，tan 可达1.2，通过控制环化度可以调节阻尼温度范围。这种新型弹性体有望为阻尼材料的发展做出贡献。
