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ABSTRACT A novel bisphthalonitrile monomer containing allyl groups (DBPA-Ph) had been synthesized via the reaction of diallyl bisphenol A (DBPA) and 4-nitrophthalonitrile. The chemical structure of DBPA-Ph was confirmed by 1HNMR, 13CNMR, and FTIR spectroscopy. The curing behaviors and processability of DBPA-Ph were studied by differential scanning calorimetry (DSC) and dynamic rheological analysis. The monomer manifested a two-stage thermal polymerization pattern. The first stage was attributed to the polymerization of allyl groups and the second to the ring-form polymerization of cyano groups. The result of dynamic rheological analysis indicated the monomer had wide curing window and the self-catalyzed curing behavior. DBPA-Ph polymers were prepared from the thermal polymerization with short curing time, showing high glass transition temperature (>350°C) and attractive thermal decomposition temperature (>430°C). The outstanding glass transition temperature, desirable thermo-oxidative stabilities, good processability and sound process conditions could provide more applications to the DBPA-Ph polymers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41203. [ABSTRACT FROM AUTHOR]

Graphene nanoplatelet reinforced semi-crystal poly(arylene ether nitrile) (PEN/GN) nanocomposites were prepared by an economically and environmentally friendly method of twin-screw extrusion technique. The feasibility of using PEN/GN nanocomposites was investigated by evaluating their thermal behaviors, mechanical, and morphological properties. Thermal studies revealed that GN could act as nucleating agents but decreased the whole crystallinity in/of PEN/GN nanocomposites. Mechanical investigation manifested that GN had both strengthening effect (increase in flexural modulus and strength) and toughening effect (rise in the elongation and impact strength) on the mechanical performance of semi-crystal PEN nanocomposites. Heat treatment can further increase their mechanical performances due to the increased crystallinity and release of inner stress. With the small addition of GN (<5 wt%), the morphology of PEN was changed from brittle to ductile, and GN showed good dispersion and adhesion in/to the PEN matrix. This work shows that in the semi-crystal polymer/filler systems, besides the dispersion states of fillers and interactions between fillers and polymer matrices, the crystallinity of the nanocomposites affected by the existence of filler and the residual stress are also two key factors determining the mechanical properties. POLYM. COMPOS., 35:404-411, 2014. © 2013 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

An easy and efficient approach by using carboxyl functionalized CNTs (CNT-COOH) as nano reinforcement was reported to develop advanced thermosetting composite laminates. Benzoxazine containing cyano groups (BA-ph) grafted with CNTs (CNT- g-BA-ph), obtained from the in situ reaction of BA-ph and CNT-COOH, was used as polymer matrix and processed into glass fiber (GF)-reinforced laminates through hot-pressed technology. FTIR study confirmed that CNT-COOH was bonded to BA-ph matrices. The flexural strength and modulus increased from 450 MPa and 26.4 GPa in BA-ph laminate to 650 MPa and 28.4 GPa in CNT- g-BA-ph/GF composite, leading to 44 and 7.5% increase, respectively. The SEM image observation indicated that the CNT-COOH was distributed homogeneously in the matrix, and thus significantly eliminated the resin-rich regions and free volumes. Besides, the obtained composite laminates showed excellent thermal and thermal-oxidative stabilities with the onset degradation temperature up to 624°C in N2 and 522°C in air. This study demonstrated that CNT-COOH grafted on thermosetting matrices through in situ reaction can lead to obvious mechanical and thermal increments, which provided a new and effective way to design and improve the properties of composite laminates. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]