PA66/6的制备及性能

以己二酸己二胺盐(AH Salt)、己内酰胺(CPL)为原料,通过熔融缩聚法制备系列配比的共聚酰胺66/6(PA66/6)。利用傅立叶变换红外光谱仪、核磁共振波谱仪、X射线衍射仪、差示扫描量热仪、热重分析仪和万能材料试验机等表征其结构与性能。结果表明,经熔融缩聚法可成功制备PA66/6,其分子结构中以稳定的α晶型为主,当AH Salt与CPL比例接近1∶1时,有利于不稳定γ晶型的形成;与聚酰胺6 (PA6)或聚酰胺66 (PA66)相比,由于共聚单体的引入,PA66/6分子链规整性降低、分子内及分子间作用力减小,其熔点、结晶度、拉伸强度均有所下降,但断裂伸长率提高,并且热稳定性良好;当AH Salt与CPL质量比为40∶60时,熔点最低降至169.7℃,结晶度为16.2%,拉伸强度最低为33.9MPa,断裂伸长率提高至122.9%,表明共聚改性可有效地提高PA66/6的韧性和加工性能。

Preparation and Properties of Co-polyamide 66/6

Co-polyamide 66/6 (PA66/6) was prepared by melt polycondensation using hexane diamine adipate (AH Salt) and caprolactam (CPL) as raw materials. The chemical structure and properties of co-polyamide 66/6 were characterized by Fourier transform infrared spectroscopy,nuclear magnetic resonance spectroscopy,X-ray diffractometer,differential scanning calorimetry, thermogravimetric analysis and universal material testing machine. The results show that PA66/6 can be successfully prepared by melt polycondensation. The stable alpha-crystalline form is the main molecular structure of PA66/6,and it is more conductive to the formation of unstable gamma-crystalline form when the ratio of AH Salt to CPL is close to 1∶1. The introduction of comonomers reduces the regularity of PA66/6 chains and decreases the intermolecular interaction force. Compared with polyamide 66 (PA66) and polyamide 6 (PA6),the melting point,crystallinity and tensile strength of PA66/6 are reduced while the elongation at break is increased with a good thermal stability. When the mass ratio of AH Salt to CPL is 40∶60,the melting point is reduced to 169.7℃, the crystallinity is 16.2%,the tensile strength is reduced to 33.9 MPa,but the elongation at break reached to 122.9%,indicating that the toughness and processability of PA66/6 can be improved effectively by copolymerization modification.