Summary: | 博士 === 國立交通大學 === 應用化學系 === 89 === The object of this study was investigated the applications of different poly(oxyalkylene)amine derivatives in the field of compatibilizer, electrostatic dissipation and epoxy curing.
The in situ formed poly(oxypropylene)-amide grafted polypropylene(PP-g-MA-co-POPs) were used as compatibilizers for the PA6/PP blends. The compatibilization effect was examined in terms of morphology, thermal and mechanical properties. Using these PP-g-MA-co-POP copolymers, the compatibilized blends show improvements in mechanical properties, including Izod impact strength and tensile toughness, over a conventional compatibilizer. The suitable molecular weight of the poly(oxypropylene) diamines in the range of 230 to 2000 is the key factor to act as an effective compatibilizer. During the compounding process, these compatibilizers further react with PA6 in situ to afford the mixture of PP-g-MA-co-POP-PA6, PP-g-MA-co-POP-co-PA6 and/or PP-g-MA-co-PA6 copolymers, which further improves the compatibilizing effect. However, the synthesized SMA-co-M-2070-co-DAP copolymers are less effective compatibilizers for the PA6/PS blends due to less interactions of M-2070 with PA6. The suitable molecular weight of the poly(oxyalkylene)amines and the PS backbone is the key factor to act as an effective compatibilizer.
The electrostatic dissipating ability, probed by surface resistivity, of the poly(oxyalkylene)amine derived epoxies and polyesteramides is found to be affected by the nature, mobility and the weight content of poly(oxyethylene) segment in the polymer backbone, as well as the degree of crystallinity. The surface resistivity decrease is proportion to the nature, mobility and the weight content of poly(oxyethylene) segment and adversely affects by the degree of crystallinity. Comparing with PEG-2000 and ED-2001 derived polyesteramides, the presence of amide group can enhance the hydrophilic property. The polymer surfaces absorb moisture through hydrogen bonding by POE segment. The partial ionization of water into H+ and OH- promotes electronic conductivity. With a proper selection of mixed poly(oxyethylene-oxypropylene)diamine (25wt%) and 2-aminoethanol (9wt%), the DGEBA cured polymer was extremely ductile in appearance and shown over 500 % elongation at break under the mechanical tests. The high flexibility is rationalized by the balanced chemical structure of poly(oxyalkylene) segments and bisphenol-A distributed in a slightly crosslinking system.
A family of novel Mannich bases were prepared from the Mannich reaction of phenols, formaldehyde, and poly(oxyalkylene)diamines with different molar ratios. The use of these novel Mannich bases for epoxy curing allowed us to study the structure/property relationship. By varying the ratio of phenols/amine and chemical structure of the starting poly(oxyalkylene)diamine, a series of products consisting of multiple functionalities of primary/secondary amines, phenols, and polyethers were prepared. The curing properties of these products toward diglycidyl ether of bisphenol-A (DGEBA) were examined by a differential scanning calorimeter (DSC). Mechanical properties of the cured polymers were also tested. The important features for these structures and curing properties were noticed: (1) Compared with poly(oxyalkylene)amines, the built-in phenols in the structures of Mannich bases can function as a accelerator for amine curing toward diglycidyl ethers which made Mannich bases exhibit a high curing rate (2) the tailored Mannich structures had a diversity of consecutive amine and phenol curings under catalytic (triphenyl phosphine) or different temperature conditions in a stepwise manner, which affected cured properties accordingly. (3) the polymers cured by the Mannich bases had demonstrated an improved mechanical properties, including tensile and flexural strength, over materials cured by the corresponding poly(oxyalkylene)diamines. The curing profiles and the mechanical properties of the cured polymers can be correlated with the Mannich structural variations.
These NP/DCPD adducts mixed with novolak (PF1120) or JeffamineR D-400 amine as co-curing agents, the tricyclodecane structure was introduced into the epoxy network and resulted an improvement of flexibility. The improvement in tensile strength and elongation has been shown by using NP/DCPD derived Mannich amine as curing agents in comparison with poly(oxypropylene) diamine at 400 molecular weight and diethylenetriamine.
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