The effect of hydrogen bonding on the physical and mechanical properties of rigid-rod polymers

Effects of heat treatments and cross‐linking on the crystal structure and torsional properties of polyester fibers

“…The HTPET monofilaments had the highest torsional modulus of 1.1 GPa followed by the PET (0.8 GPa) and PA66 (0.6 GPa) monofilaments, and this phenomenon can be explained by the difference in their rigidity and length of molecular chains 21 . The torsional modulus of different types of PPTA fibers generally range between 1.1 and 1.9 GPa 22–24 . In this work, the torsional modulus of HTPET was equivalent to that of PPTA (1.1 GPa) 24 .…”

Effects of heat treatments and cross‐linking on the crystal structure and torsional properties of polyester fibers

“…The HTPET monofilaments had the highest torsional modulus of 1.1 GPa followed by the PET (0.8 GPa) and PA66 (0.6 GPa) monofilaments, and this phenomenon can be explained by the difference in their rigidity and length of molecular chains 21 . The torsional modulus of different types of PPTA fibers generally range between 1.1 and 1.9 GPa 22–24 . In this work, the torsional modulus of HTPET was equivalent to that of PPTA (1.1 GPa) 24 .…”

Novel Sulfonated Co-poly(ether imide)s Containing Trifluoromethyl, Fluorenyl and Hydroxyl Groups for Enhanced Proton Exchange Membrane Properties: Application in Microbial Fuel Cell

“…The higher thermal stability of the DHN-XX copolymers in comparison to the analogous DAN-XX copolymers is due to the formation of additional intermolecular hydrogen bonds between two phenolic −OH groups of adjacent chains in DHN-XX. 35 As usual, none of the copolymer membranes showed any glass transition or melting until 300 °C. 11 Stress−strain curves of DHN-XX copolymer membranes, both in dry and wet states, are provided in Figure 8.…”

“…DHN-XX exhibited higher T d,10 values than DAN-XX [sulfonated copoly­(ether imide)­s without hydroxyl groups] and Nafion 117. The higher thermal stability of the DHN-XX copolymers in comparison to the analogous DAN-XX copolymers is due to the formation of additional intermolecular hydrogen bonds between two phenolic −OH groups of adjacent chains in DHN-XX . As usual, none of the copolymer membranes showed any glass transition or melting until 300 °C …”

“…The initial storage modulus values of DHN-XX (5.5–3.7 GPa) were much higher than those of the corresponding DAN-XX copolymer membranes (3.7–3.3 GPa) having no −OH groups . The more rigid nature of DHN-XX was attributed to the formation of additional intermolecular hydrogen bonds by the −OH groups with the adjacent polymer chains …”

Synthesis and Properties of Functionalized Polybenzimidazoles for High-Temperature PEMFCs

“…5,6,9 Although intramolecular O-H 3 3 3 N bonds can be formed, intermolecular N-H 3 3 3 O bonds were also formed as suggested in Figure 2b, 6 and the intermolecular hydrogenbonding energy per PIPD repeat unit was reported to be -22.6 kcal/mol 9 or -20.8 kcal/mol. 6 Another possible explanation for the low polymer solubility is cross-linking of polymer chains through phosphate bridges. The esterification of hydroxy groups by phosphoric acid is well documented in the literature.…”

Effects of heat treatments and cross‐linking on the crystal structure and torsional properties of polyester fibers

“…The HTPET monofilaments had the highest torsional modulus of 1.1 GPa followed by the PET (0.8 GPa) and PA66 (0.6 GPa) monofilaments, and this phenomenon can be explained by the difference in their rigidity and length of molecular chains 21 . The torsional modulus of different types of PPTA fibers generally range between 1.1 and 1.9 GPa 22–24 . In this work, the torsional modulus of HTPET was equivalent to that of PPTA (1.1 GPa) 24 .…”

Novel Sulfonated Co-poly(ether imide)s Containing Trifluoromethyl, Fluorenyl and Hydroxyl Groups for Enhanced Proton Exchange Membrane Properties: Application in Microbial Fuel Cell

“…The higher thermal stability of the DHN-XX copolymers in comparison to the analogous DAN-XX copolymers is due to the formation of additional intermolecular hydrogen bonds between two phenolic −OH groups of adjacent chains in DHN-XX. 35 As usual, none of the copolymer membranes showed any glass transition or melting until 300 °C. 11 Stress−strain curves of DHN-XX copolymer membranes, both in dry and wet states, are provided in Figure 8.…”

“…DHN-XX exhibited higher T d,10 values than DAN-XX [sulfonated copoly­(ether imide)­s without hydroxyl groups] and Nafion 117. The higher thermal stability of the DHN-XX copolymers in comparison to the analogous DAN-XX copolymers is due to the formation of additional intermolecular hydrogen bonds between two phenolic −OH groups of adjacent chains in DHN-XX . As usual, none of the copolymer membranes showed any glass transition or melting until 300 °C …”

“…The initial storage modulus values of DHN-XX (5.5–3.7 GPa) were much higher than those of the corresponding DAN-XX copolymer membranes (3.7–3.3 GPa) having no −OH groups . The more rigid nature of DHN-XX was attributed to the formation of additional intermolecular hydrogen bonds by the −OH groups with the adjacent polymer chains …”

Synthesis and Properties of Functionalized Polybenzimidazoles for High-Temperature PEMFCs

“…5,6,9 Although intramolecular O-H 3 3 3 N bonds can be formed, intermolecular N-H 3 3 3 O bonds were also formed as suggested in Figure 2b, 6 and the intermolecular hydrogenbonding energy per PIPD repeat unit was reported to be -22.6 kcal/mol 9 or -20.8 kcal/mol. 6 Another possible explanation for the low polymer solubility is cross-linking of polymer chains through phosphate bridges. The esterification of hydroxy groups by phosphoric acid is well documented in the literature.…”

Effects of heat treatments and cross‐linking on the crystal structure and torsional properties of polyester fibers

“…The HTPET monofilaments had the highest torsional modulus of 1.1 GPa followed by the PET (0.8 GPa) and PA66 (0.6 GPa) monofilaments, and this phenomenon can be explained by the difference in their rigidity and length of molecular chains 21 . The torsional modulus of different types of PPTA fibers generally range between 1.1 and 1.9 GPa 22–24 . In this work, the torsional modulus of HTPET was equivalent to that of PPTA (1.1 GPa) 24 .…”

Novel Sulfonated Co-poly(ether imide)s Containing Trifluoromethyl, Fluorenyl and Hydroxyl Groups for Enhanced Proton Exchange Membrane Properties: Application in Microbial Fuel Cell

“…The higher thermal stability of the DHN-XX copolymers in comparison to the analogous DAN-XX copolymers is due to the formation of additional intermolecular hydrogen bonds between two phenolic −OH groups of adjacent chains in DHN-XX. 35 As usual, none of the copolymer membranes showed any glass transition or melting until 300 °C. 11 Stress−strain curves of DHN-XX copolymer membranes, both in dry and wet states, are provided in Figure 8.…”

“…DHN-XX exhibited higher T d,10 values than DAN-XX [sulfonated copoly­(ether imide)­s without hydroxyl groups] and Nafion 117. The higher thermal stability of the DHN-XX copolymers in comparison to the analogous DAN-XX copolymers is due to the formation of additional intermolecular hydrogen bonds between two phenolic −OH groups of adjacent chains in DHN-XX . As usual, none of the copolymer membranes showed any glass transition or melting until 300 °C …”

“…The initial storage modulus values of DHN-XX (5.5–3.7 GPa) were much higher than those of the corresponding DAN-XX copolymer membranes (3.7–3.3 GPa) having no −OH groups . The more rigid nature of DHN-XX was attributed to the formation of additional intermolecular hydrogen bonds by the −OH groups with the adjacent polymer chains …”

Synthesis and Properties of Functionalized Polybenzimidazoles for High-Temperature PEMFCs

“…5,6,9 Although intramolecular O-H 3 3 3 N bonds can be formed, intermolecular N-H 3 3 3 O bonds were also formed as suggested in Figure 2b, 6 and the intermolecular hydrogenbonding energy per PIPD repeat unit was reported to be -22.6 kcal/mol 9 or -20.8 kcal/mol. 6 Another possible explanation for the low polymer solubility is cross-linking of polymer chains through phosphate bridges. The esterification of hydroxy groups by phosphoric acid is well documented in the literature.…”