Colorless Semi-Alicyclic Copolyimides with High Thermal Stability and Solubility

A series of colorless copolyimide films with high thermal stability and good solubility are synthesized from (trifluoromethyl)biphenyl-4,4’-diamine (TFMB) with different 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA) to 2,2-bis(3,4-dicarboxyphenyl)-hexafluoropropane (6FDA) dianhydride mole ratios through one-pot solution polycondensation. These copolyimide films exhibit excellent optical transparency (T400 > 90% and λ0 ~305–333 nm) with a thickness of 15 μm and good solubility in most organic solvents. The excellent optical properties are mainly attributed to the low inter- and intra-molecular charge transfer interactions due to the alicyclic structure and the strong electronegative CF3 groups. The glass transition temperature increases from 332 to 352 °C with increasing HPMDA content in the copolymers, while the thermal decomposition temperature is improved with increasing 6FDA content. These results indicate that the copolyimide films can be successfully utilized in the development of novel heat-resistant plastic substrates for the optoelectronic engineering applications.

High-Performance Copolymerized Poly(m-Phenylene Isophthalamide) (PMIA) Fibers Containing Ether Moiety: Preparation, Structure and Properties

Copolymerized poly (m-phenylene isophthalamide) (co-PMIA) fibers with excellent thermal stability and good mechanical properties were developed via solution polycondensation process based on m-phenylenediamine (MPD), isophthaloyl dichloride (IPC), and 3,4′-oxydianiline (3,4′-ODA). Effects of the ether moiety on the structure and properties of the copolymers were investigated. A series of co-PMIA nascent fibers were produced using wet-spinning method. The coagulation process to form co-PMIA nascent fibers were studied by examination of SEM and strength tester. The co-PMIA nascent fibers with the MPD/3,4′-ODA molar ratio of 8:2 showed an optimum dye uptake. Keywords: Copolymerization; High performance material; Wet spinning; Dyeability.

Comparative study of transparent polyimides derived from bis(ether anhydride)s and bis(ester anhydride)s using 2,2′-bis(trifluoromethyl)biphenyl-4,4′-diamine

Two series of polyimides (PIs) derived from bis(ether anhydride)s and bis(ester anhydride)s using 2,2′-bis(trifluoromethyl)biphenyl-4,4′-diamine were synthesized via solution polycondensation. The poly(ether imide)s could be formed by the conventional one-step method, while the poly(ester imide)s were only afforded by the two-step procedure. The resulting PIs had glass transition temperatures ( Tgs) in the range of 224–320°C and exhibited good mechanical properties with tensile strength in the range of 80.5–96.5 MPa, tensile moduli 2.7–6.9 GPa, and elongations at break 1.5–17.3%. It was found that the PIs derived from bis(ether anhydride)s showed higher thermal stability, better solubility, and transparency but lower Tg and higher water absorption compared with bis(ester anhydride)-based PIs due to the different ether and ester linkages.

Monodispersed ultramicroporous semi-cycloaliphatic polyimides for the highly efficient adsorption of CO2, H2and organic vapors

Monodispersed ultramicroporous semi-cycloaliphatic polyimides (sPIs) were synthesizedviasolution polycondensation and possess high uptakes for CO2, H2, aromatic and aliphatic vapors, exhibiting potential in gas storage and the recovery of toxic organic vapors.

Synthesis and properties of transparent polyimides derived from trans-1,4-bis(2,3-dicarboxyphenoxy)cyclohexane dianhydride

A series of transparent polyimides was prepared from trans-1,4-bis(2,3-dicarboxyphenoxy)cyclohexane dianhydride (trans-3,3′-CHDPA) with various aromatic diamines via one-step solution polycondensation.

Microwave-assisted solution polycondensation of l-lactic acid using a Dean–Stark apparatus for a non-thermal microwave polymerization effect induced by the electric field

The solution polycondensation of l-lactic acid (l-LA) in xylene catalyzed by Sc(OTf)3 was examined using a Dean–Stark apparatus under various microwave power conditions (100–400 W). The results indicate the existence of a non-thermal microwave effect induced by an electric field.

Synthesis and Characterization of Wholly Aromatic Poly (amide-sulfonamide)s by Solution Polycondensation

Four wholly aromatic Poly (amide-sulfonamide) s (PASAs) were synthesized by the solution polycondensation from m-chlorosulfonyl benzoyl chloride and aromatic diamines in tetramethylene sulfone and substituted 2-Piucoline as the acid acceptor. The chemical structures of PASAs were characterized by FTIR,1HNMR. Thermal properties of PASAs were investigated by TGA.