Yingchun Li

Synergistic flame retardant effects of composites containing organic montmorillonite, Nylon 6 and 2-cyclic pentaerythritoloctahydrogen tetraphosphate-4,6-benzene sulfonic acid sodium ammion-triazine

A novel P–N containing intumescent flame retardant, 2-cyclic pentaerythritoloctahydrogen tetraphosphate-4,6-benzene sulfonic acid sodium ammion-triazine (CTOB) was synthesized and used as an additive in intumescent flame retardant composites containing organic montmorillonite (OMMT) and Nylon 6. The thermal stability and flammability properties of Nylon 6, CTOB, OMMT and their composites were investigated by TGA, limiting oxygen index (LOI) and cone calorimeter tests. Synergistic effects between CTOB and OMMT in the Nylon 6/CTOB/OMM composite were observed. A combination of CTOB and OMMT improved the thermal stability and the flammability properties of Nylon 6 and increased the LOI value to 28.0%. The average and peak heat release rates of the ternary composite were reduced by about 65.7% and 49.3%, respectively, compared with those of Nylon 6. The residue generated after the cone calorimeter tests upon combustion of the ternary composite was a compact and dense char as revealed by SEM, which is critically important for an excellent flame retardant. [New Carbon Materials 2015, 30(2): 186–192]

Effect of Methyl Methacrylate Graft Acrylonitrile–Butadiene-Styrene on Morphology and Properties of Polycarbonate/Acrylonitrile–Butadiene-Styrene Blend

In order to improve the compatibility of polycarbonate (PC) and acrylonitrile– butadiene–styrene (ABS), a new type of reactive compatibilizer, methyl methacrylate graft acrylonitrile–butadiene–styrene (MABS) tetramer, was synthesized. The structure and properties of PC/ABS (70/30) blend with various MABS ratios were studied in terms of their mechanical and morphological properties. The results indicated that with the addition of MABS, the glass transition temperature (Tg) of the PC and ABS phases were closer to each other. Addition of MABS decreased the domain size of the ABS dispersed phase, making the dispersed phase well distributed, and the interfacial cohesiveness was enhanced. Notched impact strength and elongation at break of the PC/ABS (70/30) blend increased remarkably with the addition of MABS, with a small drop in the tensile strength.

Improved properties of recycled polypropylene by introducing the long chain branched structure through reactive extrusion

An approach originated from preparing long chain branched polypropylene (PP) was applied to modify the properties of recycled PP that involved reactive extrusion to introduce a branched chain structure onto recycled PP under the assistance of chemical reaction between maleic anhydride (MAH) monomer and glycidyl methacrylate (GMA) grafts. The results from Fourier transformed infrared spectroscopy (FTIR) indicated the reaction took place during melt mixing, and the intensity of ester increased with increasing amount of MAH. Several rheological plots including complex viscosity, storage modulus, loss modulus, loss tangent and Cole-Cole plot were used to investigate the rheological properties of recycled PP and modified PP with MAH, which indicated an additional longer relaxation time that was not shown in recycled PP. The effects of branched structure on melting and crystallization behaviors were also investigated, demonstrating the branched chains acted as nucleating agent. Moreover, the branched structure of modified samples gave rise to enhance mechanical properties, especially, the higher impact strength compared with recycled PP.

Improved Compatibility of Blends between Recycled Polypropylene and Polyamide 6 by the Products of Degradation

The compatibilization of recycled polypropylene in blends with polyamide 6 prepared via twin screw extruder was investigated. Reactive compatibilization between the recycled polypropylene and polyamide 6 was studied by “Molau test” and FTIR, the results showed the formation of copolymers during blending. Morphology analysis revealed the diameter of recycled polypropylene dispersed in polyamide 6 matrix decreased markedly and the boundary was obscure compared with the uncompatibilized blends by scanning electron microscopy. Moreover, enhanced interfacial adhesion between the blends components was also investigated by the tensile behavior and dynamical mechanical analysis.

Flow Behavior of Composites of PA6/Kaolin Nanoparticles

The blends of Nylon 6/Acrylonitrile-Butadiene-Styrene (ABS) with styrene-maleic anhydride (SMA) was prepared by melt blending as the compatilizer. Mechanical properties, dynamic mechanical analysis (DMA) and fracture appearances were determined. It was found that the impact and tensile strength firstly increased and then decreased along with the increase of the SMA content. The properties reached maximum values when the content of SMA was 1.5%. The results of DMA and scanning electron microscope (SEM) indicated that the addition of SMA can effectively enhance the compatibility of Nylon 6 and ABS. Key words: Nylon 6, ABS, SMA, blends, modification