双噁唑啉对尼龙6的化学改性研究

Chemical Modification of Polyamide 6 by Using Bisoxazoline Coupling Agents

在Haake转矩流变仪中对1,3-双-(2-噁唑啉基)苯(MPBO)和2,2-双-(2-噁唑啉)(BOZ)化学扩链尼龙6做了系统的研究。偶联结果表明:扩链剂(MPBO)和(BOZ)的用量均存在最佳值,用量不足时,偶联反应不充分;用量过量时,封端反应加剧,同时MPBO的扩链效果要比BOZ的差。当扩链剂的加入量均为最佳用量时,扩链后尼龙6的特性黏度分别从空白样的1.632dL·g-1提高到1.787dL·g-1(MPBO)和2.031dL·g-1(BOZ),此时端羧基浓度分别从初始值的7.15×10-5mol·g-1降低到3.70×10-5mol·g-1(MPBO)和2.33×10-5mol·g-1(BOZ)。反应温度对扩链反应速率的影响符合阿累尼乌斯公式,温度为260℃,扩链反应完成时间约为3min。扩链产物在高温条件下存在热降解现象。

A systematic study was conducted for the chemical chain extension of polyamide 6 （PA6） by using chain extenders 2,2＇-（1,3-phenylene）bis（2-oxazoline） （MPBO） and 2,2＇-bis（2-oxazoline） （BOZ）, respectively, in a Haake rhecord mixer. The coupling results show that the chain extension effect of BOZ is superior to that of MPBO, and both the mentioned chain extenders have their own optimal used dosage separately; the insufficient dosage used will cause insufficiency of chain extension, while excess dosage used will intensify the blocking reaction. When each own optimum dosage of the two mentioned chain extenders was used separately for the chain extension of PA6, the intrinsic viscosity of chain-extended PA6 increases from 1.632 dL·g^-1 to 1.787 dL·（g MPBO）^-1 and 2.031 dL·（g BOZ）^-1, respectively, and at the same time the carboxyl end-group concentration of chain-extended PA6 decreases from 7.15×10^-5mol·g^-1 to 3.70×10^-5mol·g^-1 and 2,33×10^-5mol·g^-1, respectively. The effect of temperature on the chain extension rate accords with the Arrhenius exponential formula, and the time needed for the completion of the chain extension reaction at 260℃ is 3 min. It was also tbund that the heat degradation of chain-extended PA6 can occur under high temperature.