Improvement of thermoplasticity for s-BPDA/PDA by copolymerization and blend with novel asymmetric BPDA-based polyimides

Hasegawa, Masatoshi; Sensui, Nobuyuki; Shindo, Yoichi; Yokota, Rikio

doi:10.1002/(sici)1099-0488(19990901)37:17<2499::aid-polb21>3.0.co;2-g

Cited by 61 publications

(37 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The possible reason for the extensive improvement is inferred as follows. It is well known that the mechanical properties of PI fibers are closely dependent on the intrinsic viscosities, intermolecular interaction, and rigidity of polymer backbone, molecular packing, and structural defects [24][25][26][27]. Currently, the intrinsic viscosities of PAA solutions range from 1.80 to 2.32 dL g -1 without the ordered regularity, implying that the enhancement in mechanical properties is not mainly affected by the intrinsic viscosity.…”

Section: Mechanical Properties Of the Co-pi Fibersmentioning

confidence: 99%

Structures and properties of polyimide fibers containing ether units

et al. 2015

View full text Add to dashboard Cite

Copolyimide (co-PI) fibers containing 4,4 0 -oxydiphthalic anhydride (ODPA) moiety into the 3,3 0 ,4,4 0 -biphenyltetracarboxylic dianhydride (BPDA)/p-phenylenediamine backbone were prepared via a two-step wet-spinning method. The processability and mechanical properties were improved significantly after the incorporation of ODPA, and the fibers exhibited an optimum tensile strength of 10.94 cN dtex -1 and modulus of 470.52 cN dtex -1 with elongation of 2.75 % at a BPDA/ODPA molar ratio of 7/3. Two-dimensional wide angle X-ray diffraction indicated that highly oriented structures and ordered molecular packing regions were formed in the fibers. Two-dimensional small angle X-ray scattering revealed that the incorporation of ODPA resulted in the reduction in radius, length, misorientation, and internal surface roughness of the microvoids in the fibers simultaneously, which was supposed to be mainly dominated for the drastically improved mechanical properties of PI fibers. Moreover, the co-PI fibers exhibited excellent thermal and thermal-oxidative stability, and the 5 % weight loss temperature was above 572 and 535°C under nitrogen and air, respectively.

show abstract

Section: Mechanical Properties Of the Co-pi Fibersmentioning

confidence: 99%

Structures and properties of polyimide fibers containing ether units

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Moreover, the synthesis of TDPA is more convenient than that of ODPA [4]. Copolymerization by incorporating monomers with flexible moieties, which disrupts the regularity of molecular chain and prevents the interaction of polymer chains, is a simple but effective way for structure modification to balance the processability and the desired properties [14,15]. For example, 3,4'-oxydianiline (3,4'-ODA) has been proved to be a diamine with polyimide derivatives having better melt flowability than polymers from its isomer 4,4'-oxydianiline(4,4'-ODA) [16].…”

Section: Introductionmentioning

confidence: 99%

Melt processable homo- and copolyimides with high thermo-oxidative stability as derived from mixed thioetherdiphthalic anhydride isomers

Han¹,

Xz²,

Xx³

2010

Express Polym. Lett.

View full text Add to dashboard Cite

Abstract.A series of homo-and copolyimides based on mixed thioetherdiphthalic anhydride isomers (mixed-TDPA) were synthesized with several kinds of aromatic diamines. The properties of these polyimides were characterized by glass transition temperature (Tg), thermal decomposition temperature, and melt processability. A series of copolyimides were prepared to achieve high Tg concurrently with melt processability by means of selecting appropriate diamines and their composition in the copolyimides. As a result, we obtained rheological information for a series of polyimide resins as a function of temperature, time and shear rate. It is found that the processability (e.g., melt viscosity of polyimides) and ultimate product properties (e.g., Tg of polyimides) can be systematically varied by changing the variety and composition of the aromatic diamines. It has been demonstrated that the incorporation of meta-or flexible diamines improve the melt processability of polyimides significantly. Meanwhile, Tg of copolyimides from dual-diamines can be predicted and regulated. Accordingly, copolyimides from 1,3-phenylenediamine (m-PDA) and 3,4'-oxydianiline (3,4'-ODA) were obtained with higher Tg and lower melt viscosity. Such correlations of chemical structures and rheological behavior provide the necessary database for tailor-making new polyimide systems with desirable processability and physical properties.

show abstract

“…Copolyimides from the reaction of various aromatic diamines with mixtures of a-BPDA and s-BPDA [1,4,5] or a-BPDA and 3,3 0 ,4,4 0 -oxydiphthalic anhydride (ODPA) [5] have been reported. The a-BPDA/s-BPDA work was conducted to introduce thermoplasticity into the polymer without lowering the T g : The a-BPDA/ODPA work was performed to develop a melt processable polymer with a high T g and good thermo-oxidative stability.…”

Section: Introductionmentioning

confidence: 99%