Cyclic polymers possess properties that are significantly different from their linear analogs, such as higher densities, smaller hydrodynamic volumes, and higher glass transition temperatures. Poly(4-methyl-1-pentene) (PMP), a linear polyolefin, is a commercial transparent thermoplastic and has applications in packaging materials and release membranes. Polymerizing 4-methyl-1-pentyne with a tungsten alkylidyne catalyst and subsequent hydrogenation (>99%) provided cyclic poly(4-methyl-1-pentene) (c-PMP). Evidence of a cyclic topology comes from rheology/viscosity studies, light scattering measurements, and size-exclusion chromatography. Importantly, atactic c-PMP exhibits a T_g (39 °C) 10 °C higher than the linear analog. A 15 g-scale cyclic polymerization was also achieved with 1-pentyne. Subsequent hydrogenation yielded 10 g of cyclic poly(1-pentene). Measurements of initial rates during the polymerization of 1-pentyne reveal a catalyst activity of 180,000,000 g/mol_cat/h.

中文翻译：

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环状聚（4-甲基-1-戊烯）：透明环状聚合物的高效催化合成

环状聚合物具有与其线性类似物明显不同的性质，例如更高的密度，更小的流体力学体积和更高的玻璃化转变温度。聚（4-甲基-1-戊烯）（PMP）是一种线性聚烯烃，是一种商用透明热塑性塑料，可用于包装材料和离型膜。将4-甲基-1-戊炔与亚烷基钨炔催化剂聚合并随后氢化（> 99％），得到环状聚（4-甲基-1-戊烯）（c -PMP）。循环拓扑的证据来自流变/粘度研究，光散射测量和尺寸排阻色谱法。重要的是，无规c -PMP具有T _g（39°C）比线性模拟量高10°C。用1-戊炔也实现了15g规模的环状聚合。随后氢化得到10g环状聚（1-戊烯）。1-戊炔聚合过程中初始速率的测量表明催化剂活性为180,000,000 g / mol _cat / h。