🏛️國立陽明交通大學機構典藏

Search Results

Now showing 1 - 4 of 4

Reactive compatibilization of polyamide-6 (PA 6)/polybutylene terephthalate (PBT) blends by a multifunctional epoxy resin
(2000-01-01)
Chiou, KC
;
Chang, FC
;
應用化學系
;
Department of Applied Chemistry
A multifunctional epoxy resin has been demonstrated to be an efficient reactive compatibilizer for the incompatible and immiscible blends of polyamide-6 (PA 6) and polybutylene terephthalate (PBT). The torque measurements give indirect evidence that the reaction between PA and PET with epoxy has an opportunity to produce an in situ formed copolymer, which can be as an effective compatibilizer to reduce and suppress the size of the disperse phase, and to greatly enhance mechanical properties of PA/PBT blends. The mechanical property improvement is more pronounced in the PA-rich blends than that in the PET-rich blends. The fracture behavior of the blend with less than 0.3 phr compatibilizer is governed by a particle pullout mechanism, whereas shear yielding is dominant in the fracture behavior of the blend with more than 0.3 phr compatibilizer. As the melt and crystallization temperatures of the base polymers are so close, either PA or PET can be regarded as a mutual nucleating agent to enhance the crystallization on the other component. The presence of compatibilizer and in situ formed copolymer in the compatibilized blends tends to interfere with the crystallization of the base polymers in various blends. (C) 2000 John Wiley & Sons, Inc.
Blends of poly(propylene) and polyacetal compatibilized by ethylene vinyl alcohol copolymers
(2003-08-08)
Huang, JM
;
Cheng, HJ
;
Wu, JS
;
Chang, FC
;
應用化學系
Polymer blends of poly(propylene) (PP) and polyacetal (polyoxymethylene, POM) with ethylene vinyl alcohol (EVOH) copolymers were investigated by differential scanning calorimetry (DSC), rheological, tensile, and impact measurements, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The PP-POM-EVOH blends were extruded with a co-rotating twin-screw extruder. The ethylene group in the EVOH is partially miscible with PP, whereas the hydroxyl group in the EVOH can form hydrogen bonding with POM. The EVOH tends to reside along the interface, acting as a surfactant to reduce the interfacial tension and to increase the interfacial adhesion between the blends. Results from SEM and mechanical tests indicate that a small quantity of the EVOH copolymer or a smaller vinyl alcohol content in the EVOH copolymer results in a better compatibilized blend in terms of finer phase domains and better mechanical properties. (C) 2003 Wiley Periodicals, Inc.
Crystallization kinetics and morphology of binary phenolic/poly(epsilon-caprolactone) blends
(2004-01-01)
Kuo, SW
;
Chan, SC
;
Chang, FC
;
應用化學系
;
Department of Applied Chemistry
For the first time, quantitative analyses of the crystallization kinetics, surface free energy of chain folding, and morphology in phenolic/poly(epsilon-caprolactone) (PCL) binary blends have been studied. The spherulite growth rate and the overall crystallization rate depend on the crystallization temperature and PCL content in the blend. In addition, the crystallization and melting temperatures of the PCL phase decrease with an increase in the phenolic content. An Avrami analysis shows that the addition of phenolic to PCL results in a decrease in the overall crystallization rate of the PCL phase. The presence of an amorphous phenolic phase results in a reduction in the rate of the spherulite growth of PCL. The surface free energy of folding increases with increasing phenolic content, and the crystal thickness of a phenolic/PCL blend, according to small-angle X-ray scattering (SAXS), is greater than that of pure PCL because of the increase in the surface free energy of chain folding and the decrease in the degree of supercooling. The observed domain size of the crystalline/amorphous phase (5.9 nm) from SAXS is also consistent with that from solid-state NMR (3-20 nm). All these results indicate that the crystallization ability of PCL decreases with increasing phenolic content in the blends. (C) 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 117-128,2004.
Simultaneous preparation of PI/POSS semi-IPN nanocomposites
(2006-03-24)
Chen, WY
;
Ko, SH
;
Hsieh, TH
;
Chang, FC
;
Wang, YZ
This investigation presents a simultaneous and convenient approach to produce a high-performance polyimide with a low dielectric constant by introducing the octa-acrylated polyhedral oligomeric silsesquioxane (methacrylated-POSS) into a polyimide matrix to form polyimide semi-interpenetrating polymer network (semi-IPN) nanocomposites. The differential scanning calorimetry (DSC) and Fourier-transform infrared (FT-IR) results indicate that the self-curing of methacrylated-POSS and the imidization of polyamic acid (PAA) occurs simultaneously. The morphology of a semi-IPN structure of polyimide[POSS-PI/POSS nanocomposites with POSS nanoparticles embedded inside the matrix is elucidated. The POSS particles are uniform and are aggregated to a size of approximately 50-60 nm inside the polyimide matrix. The interconnected POSS particles are observed at high POSS content. The structure is highly crosslinked, so the PI/POSS nanocomposites have an enhanced glass transition temperature. The high porosity of the PI/POSS nanocomposites markedly reduces the dielectric constant of PI because of the nanometer-scale porous structure of POSS.

學術出版;;Publications

Browse

Filters

Settings

Sort By

Results per page

🏛️國立陽明交通大學機構典藏

Search Results