Thermal stabilization of poly(alkylene carbonate)s
Thermal stabilization of poly(alkylene carbonate)s
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DOI：
10.1002/pol.1980.130180210
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发表时间：
1980-02
期刊：
影响因子：
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通讯作者：
D. D. Dixon-D.;M. E. Ford;G. Mantell
中科院分区：
文献类型：
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作者：
D. D. Dixon-D.;M. E. Ford;G. Mantell
(6) PPC二苯基氯氯- 294二苯基磷酸NZ 215 225封端反应持续时间。纯度，分离，端封聚合物的收率。用珀金-埃尔默tgs - 1b热重系统进行TGA的气氛。通过将0.005 g聚合物样品以2.5℃/min的速度从初始温度120℃加热到观察到样品重量损失5%的温度来测定。Qoly（碳酸乙烯）。聚碳酸丙烯。氧-磷键（表2）或氧-硫键（表111）能将聚碳酸烷基烯的分解温度提高到250℃，各种各样的试剂都能很容易地实现聚碳酸烷基烯的末端功能化。一般的实验程序包括适当的聚碳酸酯溶液（5克）(4)和末端覆盖试剂（0.05摩尔）在氯仿（50毫升）中在室温下搅拌2-6小时。通过对产物的红外分析来判断反应是否完成。在3480和3640 cm-'处，未处理的聚碳酸烷基烯不存在自由羟基的特征。缓慢添加甲醇（100毫升在30分钟内），过滤，干燥提供高产量的端封聚（碳酸烷基烯）。（其他实验数据见表1-111）在聚碳酸烷基烯的端盖过程中，亲核末端羟基被反应性较低的基团（如醋酸酯、聚氨酯、磺酸盐）所取代。虽然通过断链解聚的潜力不受转化的影响，但通过解链解聚[式(2)]被阻止了。
(6) PPC Diphenyl Chlaro- 2 94 Diphenyl Phosphate NZ 215 225 aDuration of end-capping reaction. bYield of pure, isolated, end-capped polymer.'Atmosphere under which TGA performed with a Perkin-Elmer TGS-1 B thermogravimetric system. dDetermined by heating a 0.005-g sample, of polymer at 2.5" C/min from an initial temperature of 120 C to the temperature at which a loss of 5% of sample weight was observed. qoly (ethy1ene carbonate). Poly (propy1ene carbonate). oxygen-phosphorus (Table II), or oxygen-sulfur (Table 111) bonds can raise the decomposition temperature of the poly (alky1ene carbonate) s to 250 C. Terminal functionalization of poly (alky1ene carbonate) s is readily effected with a wide variety of reagents. A general experimental procedure consists of solution of the appropriate polycarbonate (5 gm)(4) and end-capping reagent (0.05 mole) in chloroform (50 ml) at room temperature with stirring for 2-6 hr. Completion of reaction is judged by infrared analysis of the product. Bands at 3480 and 3640 cm-', which are characteristic of free hydroxy groups of untreated poly (alky1ene carbonate) s, are absent in end-capped polymer. Slow addition of methanol (100 ml in 30 min), filtration, and drying provide end-capped poly (alky1ene carbonate) in high yield.(See Tables 1-111 for additional experimental data.)During end capping of the poly (alky1ene carbonate), nucleophilic terminal hydroxy groups are replaced with less reactive groupings (eg, acetates, urethanes, sulfonates). Although the potential for depolymerization via chain scission is not affected by the transformation, depolymerization via chain unzipping [eq.(2)] is prevented.