Nylon-6/PEO物性分析及Nylon-6/6T固態動力學研究

Abstract

In this work, three topical subjects were investigated. We have synthesized nylon-6/polyethylene oxide (PEO) copolymer system based on feed ratio of PEO (0~10 wt %) through condensation polymerization. The structure of copolymer was confirmed by Fourier transform infrared (FTIR) spectroscopy and verified by 1H nuclear magnetic resonance (1H NMR). The molar mass was investigated by performing basic analyses such as relative viscosity (RV), gel permeation chromatograph (GPC) and amino-end group analysis. Notably, the results from RV and GPC reveal a reverse trend, mainly due to the different solvent characters between HFIP and sulfuric acid. The first topic was concentrated on the physical properties of the copolymers. The thermal decomposition trace of the copolymer was similar to that of nylon-6. Differential scanning calorimetry (DCS) data on the copolymers demonstrate that their melting point and glass point values do not change significantly. The DMA-determined agrees closely with that determined by mechanical testing. The plasticizing effect of the soft segments of PEO increases the mobility of the molecular chain in the copolymers. Consequently, the Tg of copolymers declines as the PEO content increases. The melt viscosity varied insignificant with PEO content less than 10 wt% at a shear rate of 104 s_1. The crystalline structure of the copolymers was examined by wide-angle X-ray diffraction (WAXD). The dominant crystalline structure was dramatically converted from α form to γ form when PEO was incorporated into the copolymers. The copolymers with 6 wt % and 8 wt % PEO had seven to ten times greater elongation at breakage. At 10 wt% PEO copolymer, the tensile strength is 57 MPa. The value is approximately 12 MPa lower, than those of neat nylon-6. The neat nylon-6 has a modulus of 2.7 GPa, while copolymer with 10 wt % PEO loading has a reduced modulus of 1.6 GPa. The Izod impact strength of the copolymers is better than that of neat nylon-6. Related results reveal that adding 10 wt % PEO to copolymers increased Izod impact strength to 40 J/m —around double that of neat nylon-6. The HDT of copolymers with 10 wt % PEO decreased the temperature from 172.9 to 167.1oC. The second topic was focused on the specific function of copolymers in a fiber form. The partially oriented yarns (POYs) approximately 70den/24f was obtained through melt-spinning and draw textured yarn (DTYs) around 60den/24f were followed. All of the fibers were tested in tensile strength, elongation. However, in all case, the tensile strength exceeded 4.5g/den, indicating that the fibers satisfied the requirements of fabric. The BWS values of 10 wt% PEO POY was around 6.2 %, higher than that of neat nylon-6 fiber. DTYs exhibit similar behavior. The WAXD results for sheets were the opposite of those for fibers. In POYs testing, the dramatically change from γ phase to α phase. After draw texturing process, the crystalline structure was completely converted to α form. Introducing 10 wt % PEO into nylon-6 increased its MR value from 6.9 to 9.81 at 34oC and an RH of 90 %; the q max (warm/cool feeling) of was enhanced from o.74 to 1.15 W/cm2. At an RH of 90 % and a temperature of 34oC, the surface resistivity of the fabric was improved from 3.26×1010 to 1.54×109 Ω/sq when 8 wt % PEO was introduced into nylon-6. The third topic was specialized in the solid state polycondensation. The structure of nylon-6/6T (40 mole %) copolymer was confirmed by FTIR spectroscopy and verified by 1H NMR. Thereafter, the molecular mass was determined by amino end group analysis depend on varied reacted temperature and varied reacted time. The reactive rate was obtained by calculation of the decline of the amino end groups. Eventually the activation energy and the frequency collision of the copolymer were determined by plotting of ln k versus 1/T. In our study, the activation energy and frequency collision were 9.78 kcal/mole and 1.364 × 101 [kg][mmole]-1[hr]-1, respectively.