扩链剂亚磷酸三苯酯对r-PETG结构与性能的影响

以亚磷酸三苯酯(TPPi)为扩链剂,通过反应加工技术对回收的聚对苯二甲酸乙二醇酯-1,4-环己烷二甲醇酯(rPETG)进行扩链改性。采用旋转流变仪、红外光谱仪和凝胶渗透色谱仪研究了TPPi添加量对r-PETG的结构与性能的影响。结果表明,当TTPi质量分数为2.0%时,r-PETG的数均相对分子量(Mn)由2.52×10~4提高到3.35×10~4;端羧基含量由100mol/kg降低到50mol/kg;零剪切黏度(η_0)由3435.8Pa·s增至27944.5Pa·s;特征松弛时间(τ0)由0.94s延长到30.91s;拉伸强度从41.2MPa增加到了62.3MPa,无缺口冲击强从38.4kJ/m~2大幅度提高至66.8kJ/m~2。改性后r-PETG分子链的结构类型没有变化,仍保持线型链结构。

Effect of Chain Extender(Triphenyl Phosphite) on the Structure and Properties of r-PETG

The chain-extended recycled-poly(ethylene terephthalate glycol-modified)(r-PETG) was modified by means of reactive processing in the presence of triphenyl phosphite (TPPi).Through infrared spectrometer (IR),rotational rheometer and gel permeation chromatography(GPC) measurement,the effects of TPPi dosage on the structure and rheology properties of the modified r-PETG were studied.Results show that after adding 2.0 ％ TPPi to the copolyester,the number average molecular weight(Mn) of the r-PETG increases from 2.52 × 104 to 3.35 × 104.At the same time,the end carboxyl group content of r-PETG decreases from 100 mol/kg to 50 mol/kg.Its zeroshearing viscosity (η0) increases from 3435.8 Pa·s to 27944.5 Pa· s and the characteristic relaxation time (r0)increases from 0.94 s to 30.91 s.The tensile strength increases from 41.2 MPa to 62.3 MPa and the non-notched impact strength increases from 38.4 kJ/m2 to 66.8 kJ/m2.The modified r-PETG remains the linear chain structure after the reaction.