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采用亚磷酸三苯酯(TPPi)为扩链剂,通过扩链反应来提高回收的共聚酯(r-PETG)的分子量,增加其特性黏度。采用凝胶渗透色谱(GPC)、熔融指数仪和红外光谱(IR)考察了TPPi的用量、扩链反应温度和混炼转速对r-PETG扩链反应的影响。在最佳反应条件(TPPi为2.0%、温度200℃、转速60 r/min)下,r-PETG的熔体流动速率(MFR)由12.83 g/10 min降低到4.24 g/10min;数均分子量(M_n)由2.52×10~4g/mol提高到3.35×10~4g/mol,提高了33.3%;拉伸强度从41.2 MPa增加到了62.3 MPa;而无缺口冲击强度从38.4 k J/m~2大幅度提高至66.8 k J/m~2。红外光谱证实了扩链反应前、后r-PETG的分子结构没有变化。
Using triphenyl phosphite (TPPi) as the chain extender, the molecular weight of the recovered copolyester (r-PETG) is increased and its intrinsic viscosity is increased by the chain extension reaction. The effects of the amount of TPPi, chain extension temperature and mixing speed on the chain extension of r-PETG were investigated by gel permeation chromatography (GPC), melt indexer and infrared spectroscopy (IR). The melt flow rate (MFR) of r-PETG decreased from 12.83 g / 10 min to 4.24 g / 10min under the best reaction conditions (TPPi of 2.0%, temperature of 200 ℃ and rotation speed of 60 r / min); the number average molecular weight (M_n) increased from 2.52 × 10 ~ 4g / mol to 3.35 × 10 ~ 4g / mol, increased by 33.3%; the tensile strength increased from 41.2 MPa to 62.3 MPa; while the unnotched impact strength increased from 38.4 kJ / m ~ 2 Significantly increased to 66.8 k J / m ~ 2. Infrared spectroscopy confirmed that before and after the chain extension reaction, there was no change in the molecular structure of r-PETG.