New aromatic poly(amide-imide) films containing isoindoloquinazolinedione unit in the backbone chain were directly obtained by thermal cyclization of the prepolymer of poly(amic acid-carbonamide) type, i.e., poly(biphenylphthalic dianhydride-oxydianiline-4,4′-diamino-3′-carbamoyl-benzanilide) [poly(BPDA-ODA-DACB)]. The films, before heat treatment, exhibited the tensile strength of 30 ≈ 40 MPa and the tensile modulus of 1.3 ≈ 1.9 GPa. After heat treatment, the strength and modulus increased to 135 ≈ 150 MPa and 2.6 ≈ 2.7 GPa, respectively. The films remained transparent throughout the thermal treatment. The cyclized films were much more chemically resistant to alkali than the commercial products such as “Kapton” film and “P84” film, while thermal properties were comparable. The isoindoloquinazolinedione unit induced in the chain backbone on the heat treatment of the films was considered to be a major factor responsible for the superior physical properties of the films.

To prepare thermally stable and high-performance polymeric films, new solvent-soluble aromatic polyamides with a carbamoyl pendant group, namely poly(4,4′-diamino-3′-carbamoylbenzanilide terephthalamide) (p-PDCBTA) and poly(4,4′-diamino-3′-carbamoylbenzanilide isophthalamide) (m-PDCBTA), were synthesized. The polymers were cyclized at around 200 to 350 °C to form quinazolone and benzoxazinone units along the polymer backbone. The decomposition onset temperatures of the cyclized m- and p-PDCBTAs were 457 and 524 °C, respectively, lower than that of poly(p-phenylene terephthalamide) (566 °C). For the p-PDCBTA film drawn by 40% and heat-treated, the tensile strength and Young's modulus were 421 MPa and 16.4 GPa, respectively. The film cyclized at 350 °C showed a storage modulus (E′) of 1 × 10¹¹ dyne/cm² (10 GPa) over the temperature range of room temperature to 400 °C.

A new thermally stable, high strength and high modulus aromatic polyamide film was obtained via the formation of the molecular composite of p-PDCBTA and P-LCl. The two polymers exhibited good miscibility identified with the measurement of dynamic mechanical property and FTIR spectra. By the combination of drawing by 40% and subsequent heat treatment, the tensile property of the composite film could be achieved to the strength of 450 MPa and the modulus of 24 GPa, which were sustainable upto 400 °C.

Poly(butylene terephthalte-co-oxybenzoate) (PBOT) was synthesized by melt trans-esterification of poly(butyldne terephthalate(PBT) and p-acetoxybenzoic acid(ABA)at 250, 260, and 270 ℃ with the compositions of PBT/ABA of 4/6, 5/5, 6/4. The sequence analysis of PBOT with a 1H FT-NMR indicated that the number of consecutive oxybenzoate units range from 1.2 to 1.5, which is larger than that of the corresponding poly(ethylene terephthalate)(PET)/ABA(PEOT) obtained at the same reaction conditions as the PBOT. The difference in the block length influenced the thermal degradation behavior: Polyoxybenzoate(POB), PBT and PBOT showed one-step degradation whereas PBOT exhibited two-step degradation. THe results suggested that PBOT consisted of three phases of PBT-rich phase, random phase of PBT andABA, and ABA-rich phase.

Poly(butylene terephthalate-co-oxybenzoate)(PBOT) containing mesogenic oxybenzoate units in the main chain was synthesized through ester exchange reaction by melt mixing of poly(butylene terephthalate)(PBT) and p-acetoxybenzoic acid(ABA). From the kinetics of the copolymerization reaction, the activation energies and the rate constants of homopolymerization and copolymerization, kb and kc, could be determined. From the reaction conditions of different compositions, 4/6, 5/5, and 6/4 of PBT/ABA, at 250, 260, and 270 ℃, it was revealed that copolymerization between PBT and ABA proceeds on a pseudo-second order reaction if the ABA content and its conversion are low. In this case, the ratio of rate constants of homopolumerization to copolymerixation was in the range from 1.08 to 3.17, indicating that the copolymer with more notable block character was obtained at the higher mole fraction of ABA and at higher temperature.

The effects of reaction variables on the degree of randomness in copolymers formed by ester interchange reaction in miscible polyester melt blends were systematically investigated using a Monte Carlo method. Three reaction variables such as the molecular weight difference between two component polymers, the blend ratio, and the reaction ratio of end attack to bond flip, were particularly considered on the cubic lattice model. Ester interchange reactions were assumed to take place during reptational chain motions. It was found that the copolymerization was dependent upon the molecular weight difference and reaction ratio: As the molecular weight difference becomes smaller and when both end attack and bond flip reactions are involved simultaneously, the copolymerization is accelerated. However, the blend ratio does not affect the copolymerization process. This result is discussed in relation to the polymer chain conformation for the ester interchange reaction. 

Various poly(p-phenylene alkylene dicarboxylates) (PPADs) were synthesized and their crystallization behavior was examined as functions of the length and the odd/even numbers of carbon atoms in the aliphatic component. PPADs with longer aliphatic units of even-numbered carbon atoms were found to crystallize faster than do those of other cases. The results are compared with the crystallization behavior of conventional poly(alkylene terephthalate)s (PATs), e.g., poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT), which have the same chemical composition as the corresponding PPAD but the reversed direction of the ester group. The effects of this structural difference on the melting temperature and the crystallization kinetics are also discussed. 

Modified poly(ethylene terephthalate) (MPET) samples of both powder and fiber types, which contain sodium 5-sulfodimethyl isophthalate as the third comonomer component, were explored as an adsorbent for the elimination of heavy metal ions, e.g., Cr3+, Pb2+, and Cd2+, in wastewater. The ions were preferentially adsorbed on finer particles at a lower temperature and pH 4 and were exothermically chemisorbed onto the MPETs via an ionic interaction. It was also found that among the ions Cr3+ is the most preferentially adsorbed, followed by Pb2+ and Cd2+ ions and the adsorption capability of MPETs increased considerably with the presence of phenol. The separation factor indicated that the MPET fiber wastes may possibly be reutilized as an economical adsorbent for heavy metal ions in wastewater.

Optimum conditions for the synthesis of PEI of considerable molecular weight have been established. Poly(ethylene terephthalate-co-isophthalate) (PETI) has been prepared through the ester interchange reaction of a blend of poly(ethylene terephthalate) (PET) and poly(ethylene isophthalate) (PEI). NMR analysis has indicated that the PETI changes from a block-type copolymer to a random type copolymer as the ester interchange reaction proceeds. If the reaction is limited to 20 min, the resulting PETI is crystallizable. The effects of catalysts that have been used during the synthesis of PEI on the characteristics of PETI are also discussed.

The effect of surface treatment at high temperatures on the morphology and mechanical behavior of Torayca T300 carbon fiber is studied. It is found that the surface treatment results in a considerable change in the surface and cross-sectional morphology of the carbon fiber. Accordingly, there arc sizable change in mechanical properties of the fiber: in particular, compressional failure mechanism changes from buckling to simple shear mode as the surface  treatment temperature increases. There is not an apparent relationship between the surface structural parameters such as surface area, pore volume, etc. and the mechanical properties such as tensile and compressive strengths.

Electrically conducting arachidic acid/polypyrrole (PPy) composite films were prepared by exposing the arachidic acid LB films containing ferric chloride to pyrrole vapor. The optimum conditions to deposit matrix LB film were the subphase temperature of 23–25°C, pH of 6.0 and ferric chloride concentration of 5.0 × 10⁻⁵M. The formation of PPy in the arachidic acid matrix LB films was confirmed by UV-visible spectra, FTIR spectra, and scanning electron micrographs. The average thickness of the composite LB films prepared at 0°C was 1525 Å. The composite films prepared at lower temperatures have more uniform surface and exhibit higher electrical conductivity than the films prepared at higher temperatures do. The in-plain conductivity and the transverse conductivity of the composite film were 10⁻³−10⁻² S/cm and 10⁻⁶S/cm, respectively, and, thus, the conductivity anisotropy was about 10³

Microstructural features of carbon fibres based on both polyacrylonitrile (PAN) and mesophase pitch (MP) are discussed in relation to their compressional performance estimated by the recoil test. The compressive strength of carbon fibres is influenced by a combination of various structural features and not by any single feature. In particular, the compressive failure strength increases linearly with increasing amounts of both inter- and intracrystalline disorder. For a given amount of disorder, the more recently developed PAN-based fibres exhibited much higher compressive failure stresses than older PAN- and MP-based carbon fibres; this is due to the more homogeneous distribution of microstructural features. In order to promote compressive strength it is suggested that all crystallite dimensions should be limited to below 5 nm whilst maintaining good orientation.

For both polyacrylonitrile homopolymer and copolymers(homo- and co-PANs) prepared in dimethylsulfoxide(DMSO) solution by radical polymerization induced by azo-bis-isobutyronitrile(AIBN), the thermal behavior studied via DSC technique was discussed in relation to the characteristics of polymers. It has been found that for the non-isothermal stabilization of homo-PANs under nitrogen and air atmospheres. the initiation and the maximum temperatures for the stabilization are not influenced by molecular weight and molecular weight distribution characteristics of polymers. However, under isothermal stabilization under air, longer time is required by the polymers with higher content of high molecular weight fraction, i.e. Mw > 3x10^5. It has also been confirmed that the addition of comonomer and air atmosphere favour the stabilization of polymers by lowering the intiation temperature, slowing down the reaction rate, and extending the temperature range within which the stabilization may be completed. From the isothermal stabilization of co-PANs. it was believed that the temperature of 240oC have practical significance.

For both homo-and co-polyacrylonitriles(homo- and co-PAN) prepared in dimethylsulfoxide(DMSO) solution by radical polymerization induced by azo-bis-isobutyronitrile(AIBN), the reaction kinetics was studied. It has been found that the polymerization rate increases with increasing concentrations of monomer and initiator, and the polymerization temperature, while molecular weight, polydispersity, and high molecular-weight-fraction(over 3x10^5 in Mw) decrease.

The polymerization factors to meet the desired physical properties of  polyacrylonitrile (PAN) spinning dope for on-line spinning were examined, The spinning dope was prepared by solution polymerization in dimethylsulfoxide solution induced by azobis-iso-butyronitrile. The physical properties of the spinning dope could be controlled by manipulating monomer concentration, initiator concentration, and polymerization temperature. At the unusually high monomer concentrations, required in the on-Iine spinning process, the polymerization of PAN exhibited a little deviation from the theoretical prediction

The distribution of microvoids in high-strength aramid fibre has been established. The tensile and compressive behaviours of both untreated and silver sulphide-impregnated Kevlar 981 fibre are reported and the results are discussed in terms of the influence of microvoids on the mechanical performance.

Modified polyethylene terephtale (M-PET) was obtained by copolymerizing dimethyl terephtalate(DMT), ethylene glycol, and dimethyl 5-sulfoisophthalate(DMS) and antistatic polyester material has been prepared by exposing M-PET containg ferric chloride to pyrrole vapor. The DMS component in M-PET was confirmed by the analysis of IR and NMR spectra. The formation of polypyrrole(PPy) in M-PET matrix was also confirmed by the analysis of IR spectrum. The changes of physical structure due to the insertion of ferric chloride and formation of PPy in M-PET have been investigated by analysing wide-angle X-ray diffraction curves. The surface of the antistatic polyester film showed the continuous phase of granular PPy which was formed through the film thickness The physical properties of antistatic polyester was satisfiable, that was, the tensile strength and the elongation at break retained 80 and 90% of those of M-PET matrix, respectively. But the modulus retained about 60% of M-PET matrix.