Browsing by Author "Chiang, CR"

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Molecular dynamics and mechanical properties correlations of PA6/PPO blends compatibilized with SMA
(1999-06-01)
Chu, PP
;
Huang, JM
;
Wu, HD
;
Chiang, CR
;
Chang, FC
The effects of the compatibilizer, styrene maleic anhydride (SMA-8% MA) upon the change of morphology and molecular dynamics of polyamide-6 (PA6) and poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) blends were investigated by means of solid-state NMR techniques. With increasing amounts of SMA, the domains correspond to PA6 and PPO are reduced and the polymer segmental mobility increased. The correlation between NMR relaxation time, T-1p(H), and the bulk mechanical properties provide a molecular level understanding of the modification of molecular dynamics by the compatibilizer (SMA). The correlation shows that the tensile strength is governed mainly by the morphology, but modulated by the PA6 crystallinity, while the tensile elongation and impact strength are closely affected by both the molecular mobility and morphology. The annealing process improved only the tensile strength, but deteriorated tensile elongation and impact strength due to the increase of PA6 crystallinity, which induced phase separation after annealing. This study raised an important point that the polymer mechanical properties are most sensitive to the molecular structure and dynamics take place within the range of 20 Angstrom to few hundred Angstrom. (C) 1999 John Wiley & Sons, Inc.
Polymer blends of PA6 and PPE compatibilized by poly[methylene(phenyleneisocyanate)] (PMPI) coupler
(1998-04-01)
Chiang, CR
;
Ju, MY
;
Chang, FC
;
應用化學系
;
Department of Applied Chemistry
An oligomeric isocyanate, poly[methylene(phenylene isocyanate)] (PMPI), is demonstrated to be an efficient reactive compatibilizer for blends of polyamide-6 (PA6) and poly(2,6-dimethyl-1,4-phenylene ether)(PPE). Use of this compatibilizer results in substantial improvements in mechanical properties. The multiple functional isocyanate acts as a coupling agent and reacts with PA6 and PPE endgroups during melt processing to produce a PA6-co-PMPI-co-PPE mixed copolymer at the interface. This in situ-formed copolymer tends to reside at the interface to reduce the melt interfacial tension and enhance interface adhesion.
Polymer blends of polyamide-6 (PA6) and poly(phenylene ether) (PPE) compatibilized by a multifunctional epoxy coupler
(1998-08-01)
Chiang, CR
;
Chang, FC
;
應用化學系
;
Department of Applied Chemistry
A tetrafunctional epoxy monomer, N,N,N'-N' -tetraglycidyl-4,4'-diaminodiphenyl methane (TGDDM),has demonstrated to be a highly efficient reactive compatibilizer in compatibilizing the immiscible and incompatible polymer blends of polyamide-6 (PA6) and poly(2,6-dimethyl-1,4-phenylene ether) (PPE). This epoxy coupler can react with both PA6 and PPE to form various PA6-co-TGDDM-co-PPE mixed copolymers. These interfacially formed PAG-co-TGDDM-co-PPE copolymers tend to anchor along the interface to reduce the interfacial tension and result in finer phase domains and enhanced interfacial adhesion. A simple one-step melt blending has demonstrated to be more efficient in producing a better compatibilized PA6/PPE blend than a two-step sequential blending. The mechanical property improvement of the compatibilized blend over the uncompatibilized counterpart is very drastic, by considering the addition of a very small amount, a few fractions of 1%, of this epoxy coupling agent. (C) 1998 John Wiley & Sons, Inc.
Polymer blends of polyamide-6 (PA6) and poly(phenylene oxide) (PPO) compatibilized by styrene-maleic anhydride (SMA) copolymer
(1997-09-01)
Chiang, CR
;
Chang, FC
;
應用化學系
;
Department of Applied Chemistry
The commercially available styrene-maleic anhydride copolymer (SMA-8% MA) has been demonstrated to be a highly effective compatibilizer for polymer blends of polyamide-6 (PA6) and poly(2,6-dimethyl-1,4-phenylene oxide) (PPO). SMA is miscible with PPO and tends to be dissolved in the PPO phase during the earlier stages of melt blending. The dissolved SMA has the chance to make contact and reacts with PA6 at the interface to form the desirable SMA-g-PA6 copolymer. This in situ-formed SMA-g-PA6 graft copolymer tends to anchor along the interface to reduce the interfacial tension and results in finer phase domains. The overall mechanical property improvement of the compatibilized blends over the uncompatibilized counterparts is drastic, especially for these PPO-rich blends. The mechanism of this conventional reactive compatibilization system has been discussed in detail. (C) 1997 Elsevier Science Ltd.
Polymer blends of polyamide-6 and poly(phenylene oxide) compatibilized by styrene-co-glycidyl methacrylate
(1996-09-26)
Chiang, CR
;
Chang, FC
;
應用化學系
;
Department of Applied Chemistry
Incompatible polymer blends between polyamide-6 (PA6) and poly(phenylene oxide) (PPO) have been compatibilized in situ by the styrene-glycidyl methacrylate (SG) reactive copolymers. The epoxy functional groups in SG copolymers can react with the PA6 amine and carboxylic endgroups at interface to form various SG-g-PA6 copolymers. These in situ-formed grafted copolymers tend to anchor along interface to function as compatibilizer of the blends. The styrene and the SG segments of the grafted copolymers are miscible (or near miscible) with PPO; whereas the PA6 segments are structurally identical with PA6 phase. The compatibilized blend, depending on quantity of the compatibilizer addition and the glycidyl methacrylate (GMA) content in the SG copolymer, results in smaller phase domain, higher viscosity, and improved mechanical properties. About 5% GMA is the optimum content in SG copolymer that produces the best compatibilization of the blends. This study demonstrates that SG reactive copolymers can be used effectively in compatibilizing polymer blends of PA6 and PPO. (C) 1996 John Wiley & Sons, Inc.
Reactive compatibilization of PET and PPE blends by epoxy couplers
(1997-07-25)
Lo, DW
;
Chiang, CR
;
Chang, FC
;
應用化學系
;
Department of Applied Chemistry
A commercially available tetrafunctional epoxy monomer was demonstrated to be an effective reactive compatibilizer for blends of poly( ethylene terephthalate) (PET) and polyphenylene ether (PPE). It requires about 10-20% by weight of a conventional reactive compatibilizer to achieve the same level of compatibilization in terms of domain size reduction and mechanical property improvement. This epoxy monomer is able to contact and react with PET and PPE simultaneously during high shear extruder blending to form the desirable PET-epoxy-PPE mixed copolymer. This mixed copolymer contains PET and PPE segments that tend to anchor at the interface to act as an efficient compatibilizer of the PET and PPE blends. (C) 1997 John Wiley & Sons, Inc.