잔류 중합용매가 Poly (2-cyano-p-phenylene terephthalamide)/NMP/CaCl2 용액 및 이로부터 제조된 섬유의 물리적 성질에 미치는 영향

Abstract

N-methyl-2-pyrrolidone (NMP)/ calcium chloride (CaCl2) 계에서 얻어진 poly (2-cyano-p-phenylene terephthalamide) (CY-PPTA) 용액으로부터 수세하여 제조된 섬유에는 극소량의 용매와 고분자 complex가 존재하는데 이것이 CY-PPTA 용액과 섬유의 물리적 성질에 미치는 영향에 대하여 고찰하였다. 물로 수세한 CY-PPTA 분말 (CYP-W)은 200-300oC 온도에서 5% 의 질량 감소가 나타났으나, 이 분말을 acetone으로 추가 세척한 CY-PPTA 분말 (CYP-A)의 경우에는 질량감소가 관찰되지 않았다. Tds-GC-MS 분석결과 증발성분의 99.7%가 NMP 인 것으로 확인되었으며, 이것은 1H/13C-NMR로도 확인되었다. 희박 용액 계에서 CYP-W와 CYP-A 모두 유사한 고유점도 값을 가졌으며, 환원점도에서 또한 유사한 농도의존성을 보였다. 고분자쇄간 상호작용이 우세한 농축 용액 계에서는 CYP-A와 CYP-W 용액이 서로 다른 동적 점도 거동을 보였다. CYP-A 용액의 경우 CYP-W 용액보다 더 높은 동적 점도 값을 나타냈으며, 전 농도 영역에서 CYP-A 용액이 보다 높은 항복 응력 값을 나타냈다. 하지만 농도에 따른 유방성 액정 거동은 두 용액 모두 유사하게 나타났으며, 편광 사진으로 관찰된 Schlierene texture도 두 용액 모두 유사한 형태로 나타났다. 그러나 기격방사로 제조된 CY-PPTA as-spun 섬유는 열처리 후 상당한 기계적 물성 감소가 나타났는데 이것은 열처리시 complex 형태로 남아있던 극소량의 NMP 증발에 따른 기공형성 때문인 것을 확인되었다.|The poly (2-cyano-p-phenylene terephthal-amide) (CY-PPTA) powder obtained by washing the polymer solutions in the mixture of N-methyl-2-pyrrolidone (NMP) and calcium chloride (CaCl2) with water (CYP-W) included a small amount of solvent molecules as a complex with polymer chains. The thermogravimetric analysis revealed that the complex was broken up and evolved 5 wt% of gaseous products over the temperature of 200 to 300oC. Analysis of evolved gases proved they are largely composed of NMP, which was further confirmed by 1H/13C-NMR analysis of the solution obtained by washing CYP-W with acetone. In addition, the effect of the residual NMP on the physical properties of the solution dope and resultant fiber of CY-PPTA was investigated. In the dilute concentration range, the solutions of CYP-W and CYP-A, obtained by washing CYP-W with acetone, exhibited almost the same intrinsic viscosity behavior and concentration dependence of reduced viscosity, suggesting that the complexed NMP molecules had little effect on the conformation of respective CY-PPTA molecules. On the other hand, two CY-PPTA solutions showed a little different behavior in dynamic viscosity in the concentrated range, indicating that the complexed NMP molecules slightly affected the intermolecular interactions of CY-PPTA molecules. Moreover, CYP-A solutions exhibited higher values of yield stress than the CYP-W solutions. However, the complex had little influence on the lyotropic liquid crystalline behavior of the polymer. Polarized optical micrographs also ascertained that both CYP-W and CYP-A solutions in the mixture of NMP and CaCl2 showed almost the same phase behavior. However, the residual NMP molecules had a notable influence on the mechanical properties of as-spun fibers obtained by direct dry jet-wet spinning of the in-situ polymerized and neutralized solution dopes of CY-PPTA in the mixture of NMP and CaCl2. Heat treatment of CY-PPTA fibers left some porous morphology on the fiber surface by evaporating residual NMP and notably reduced the tensile properties.; The poly (2-cyano-p-phenylene terephthal-amide) (CY-PPTA) powder obtained by washing the polymer solutions in the mixture of N-methyl-2-pyrrolidone (NMP) and calcium chloride (CaCl2) with water (CYP-W) included a small amount of solvent molecules as a complex with polymer chains. The thermogravimetric analysis revealed that the complex was broken up and evolved 5 wt% of gaseous products over the temperature of 200 to 300oC. Analysis of evolved gases proved they are largely composed of NMP, which was further confirmed by 1H/13C-NMR analysis of the solution obtained by washing CYP-W with acetone. In addition, the effect of the residual NMP on the physical properties of the solution dope and resultant fiber of CY-PPTA was investigated. In the dilute concentration range, the solutions of CYP-W and CYP-A, obtained by washing CYP-W with acetone, exhibited almost the same intrinsic viscosity behavior and concentration dependence of reduced viscosity, suggesting that the complexed NMP molecules had little effect on the conformation of respective CY-PPTA molecules. On the other hand, two CY-PPTA solutions showed a little different behavior in dynamic viscosity in the concentrated range, indicating that the complexed NMP molecules slightly affected the intermolecular interactions of CY-PPTA molecules. Moreover, CYP-A solutions exhibited higher values of yield stress than the CYP-W solutions. However, the complex had little influence on the lyotropic liquid crystalline behavior of the polymer. Polarized optical micrographs also ascertained that both CYP-W and CYP-A solutions in the mixture of NMP and CaCl2 showed almost the same phase behavior. However, the residual NMP molecules had a notable influence on the mechanical properties of as-spun fibers obtained by direct dry jet-wet spinning of the in-situ polymerized and neutralized solution dopes of CY-PPTA in the mixture of NMP and CaCl2. Heat treatment of CY-PPTA fibers left some porous morphology on the fiber surface by evaporating residual NMP and notably reduced the tensile properties.