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Ester Imide (ester + imide)
Selected AbstractsInfluence of azobenzene units on imidization kinetic of novel poly(ester amic acid)s and polymers properties before and after cyclodehydrationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Ewa Schab-Balcerzak Abstract In this article, the imidization reaction kinetic of novel poly(ester amic acid)s with azobenzene units as side groups was studied by dynamic experiments by means of differential scanning calorimetry. Polymers differ in the number of chromophore moieties in their repeating unit and position in which azobenzene group is attached to the polymer chain. The kinetic parameters of poly(ester amic acid)s conversion to poly(ester imide)s was compared with data calculated for parent polymer, that is, without azobenzene groups. For the first time to our knowledge, the imidization kinetic of polymers with side azobenzene groups was studied. Kinetic parameters, such as the activation energy and frequency factor were estimated with the by Ozawa model [(E(O) and A(O)), respectively] and Kissinger model [(E(K) and A(K), respectively]. The values of activation energy determined with both models were in the range 167.1,198.3 kJ/mol. The lowest activation energy of imidization reaction exhibited polymer in which azobenzene units were placed between amide linkages. Polymers were characterized by FTIR, 1H-NMR, X-ray, and UV,vis methods. The glass transition temperature of resultant poly(ester imide)s was in the range of 217,237°C. The presence of chromophore units slightly decreased Tg and significantly improved their solubility and optical properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Preparation of poly(ester imide) ultrafine fibers by gas-jet/electrospinningJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2009Bing Wang Abstract In this study, ultrafine fibers of poly(ester imide) (PEI) were produced by gas-jet/electrospinning of its solutions in mixtures of phenol and dichloromethane (DCM). The process parameters, including the solution concentration, gas flow rate, applied voltage, tip-to-collector distance (TCD), and inner diameter of the metal needle, were investigated by scanning electron microscopy. The results show that the solution concentration, gas flow rate, TCD, and inner diameter of the needle were the most important process parameters influencing the average diameter and morphology of the PEI gas-jet/electrospun fibers. An increase in the solution concentration resulted in a larger average diameter in the PEI gas-jet/electrospun fibers. Mixed-bead fibers were obtained when the concentration of PEI in phenol/DCM was below 20 wt % during gas-jet/electrospinning. A larger diameter of the capillary and a smaller gas flow rate favored the formation of ultrafine fibers with thicker fibers. Thinner and uniform PEI fibers with an average diameter of 298 nm were formed at a TCD of 25 cm. On the basis of the systematic parameters study, uniform PEI ultrafine fibers with an average diameter of 293 nm were prepared by this gas-jet/electrospinning with the following optimal process parameters: the concentration of the polymer solution was 20 wt %, the gas flow rate was 10.0 L/min, the applied voltage was 25.0 kV, the TCD was 25 cm, and the inner diameter of the metal needle was 0.24 mm. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Influence of the monomer feeding sequence on the structure and properties of thermotropic liquid-crystalline poly(ester imide)sJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008Zhenguo Chi Abstract A series of poly(ester imide)s mainly derived from N,N,-hexane-1,6-diylbistrimellitimides, 4,4,-dihydroxybenzophenone, and p -hydroxybenzoic acid were synthesized by a direct polycondensation method in benzenesulfonyl chloride, N,N,-dimethylformamide, and pyridine with different monomer feeding sequences. The molecular structures and properties of the resultant poly(ester imide)s were characterized with NMR, IR spectrometry, polarized light microscopy, wide-angle X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. The results showed that the monomer feeding sequences had a great effect on the sequential structure of the molecular chains of the copolymers and consequently on their liquid-crystalline (LC) properties, fiber-forming capability, and other properties. Thus, it is probable that one could obtain an LC poly(ester imide) with given properties by controlling the monomer feeding sequence during the polycondensation process. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Poly(ethylene terephthalate) reinforced by N,N,-diphenyl biphenyl-3,3,,4,4,-tetracarboxydiimide moietiesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 7 2002Jun Xiao Abstract Starting with 3,3,,4,4,-biphenyltetracarboxylic dianhydride and methyl aminobenzoate, we synthesized a novel rodlike imide-containing monomer, N,N,-bis[p -(methoxy carbonyl) phenyl]-biphenyl-3,3,,4,4,-tetracarboxydiimide (BMBI). The polycondensation of BMBI with dimethyl terephthalate and ethylene glycol yielded a series of copoly(ester imide)s based on the BMBI-modified poly(ethylene terephthalate) (PET) backbone. Compared with PET, these BMBI-modified polyesters had higher glass-transition temperatures and higher stiffness and strength. In particular, the poly(ethylene terephthalate imide) PETI-5, which contained 5 mol % of the imide moieties, had a glass-transition temperature of 89.9 °C (11 °C higher than the glass-transition temperature of PET), a tensile modulus of 869.4 MPa (20.2 % higher than that of PET), and a tensile strength of 80.8 MPa (38.8 % higher than that of PET). Therefore, a significant reinforcing effect was observed in these imide-modified polyesters, and a new approach to higher property polyesters was suggested. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 852,863, 2002; DOI 10.1002/pola.10169 [source] Thermal properties of biaxially deformed in situ compositesPOLYMER ENGINEERING & SCIENCE, Issue 8 2004Youngwook P. Seo The thermal properties of biaxially blown poly(etherimide) (PEI) films containing a thermotropic liquid crystalline polymer (TLCP) were studied using differential scanning calorimetry, thermogravimetric analysis, wide-angle X-ray diffraction and dynamic mechanical thermal analysis. The effects of the compatibilizer and thermal annealing on the thermal properties of biaxially oriented TLCP films were investigated. Though the compatibilizer (poly(ester imide)) improved deformation of the TLCP phase (poly ester amide) and adhesion between the matrix and the TLCP phase, which improved mechanical properties, it did not significantly affect the thermal properties of the in situ composite films. The film degradation behavior corroborated the role of the compatibilizer. Since a relatively small amount of TLCP (10 wt%) was added to the matrix and the matrix PEI was amorphous, the effect of annealing on the TLCP structure was not obvious. By the same token, while the effect of the deformation in the circumferential direction (a change in the blow-up ratio) was manifest in mechanical property improvements, its effect on the thermal properties was not obvious. All films showed similar thermal expansion behaviors, regardless of the thermal history and of the compatibilizer addition. Thus, there is an optimum amount of the compatibilizer required to obtain optimal mechanical properties for in situ composite films without causing a deterioration of their thermal properties. Polym. Eng. Sci. 44:1419,1428, 2004. © 2004 Society of Plastics Engineers. [source] | ||||||||||