Xu L.,Guangdong University of Technology |
Lei C.,Guangdong University of Technology |
Xu R.,Guangdong University of Technology |
Zhang X.,Guangdong University of Technology |
Zhang F.,Kingfa Science and Technology Company
Polymer Degradation and Stability | Year: 2016
A planar-like inorganic α-zirconium phosphate (α-ZrP) particles were modified by a kind of cyclophosphazene derivative via three-step hybridization method, first modified by melamine (MA), then combined with hexachlorocyclotriphosphazene (HCCP) through nucleophilic substitution and further integrated with excessive MA. Thus, a hybrid flame retardant (HAC) was successfully synthesized. The composites based on poly(vinyl alcohol) (PVA) and HAC were prepared by solution blending. The thermal, mechanical properties and flame retardancy of the composites were studied. It was found that HAC showed a catalytic effect in the initial decomposition stage and promoted the formation of char at high temperatures. When the content of HAC was 15 wt%, the limiting oxygen index (LOI) reached 28.4% and classified V-0 rating, whereas with the same content of fire retardant, for PVA/α-ZrP and PVA/product of MA with HCCP composites (one kind of intumescent flame retardant IFR), the LOI values were only 24.7% and 27.1%, respectively. The combination of IFR and α-ZrP could remarkably improve the yield and graphitization of char residues, make the char more stable, compact and continuous, inhibiting underlying PVA from contacting heat and oxygen. Moreover, the mechanical properties could be reinforced and toughened with certain content of HAC. © 2016 Elsevier Ltd
Lei C.,Guangdong University of Technology |
Li S.,Guangdong University of Technology |
Chen D.,Kingfa Science and Technology Co. |
Wu B.,Kingfa Science and Technology Co. |
Huang W.,Guangdong University of Technology
Journal of Applied Polymer Science | Year: 2011
The influence of 1-decene as the second monomer on the melt-grafting behavior of maleic anhydride (MAH) onto polypropylene (PP) was studied with differential scanning calorimetry and Fourier transform infrared spectroscopy. We found that the value of the grafting degree increased from 0.68% for pure MAH-g-PP to 1.43% for the system with a 1-decene/MAH molar ratio of 0.3, whereas the maximum value with styrene (St) as the second monomer was 0.98% under an St/MAH molar ratio of 1.0. Compared with the contribution of St/MAH-g-PP to the peeling strength between the PP and polyamide (PA) layer for a PP/PA laminated film, the introduction of 1-decene/MAH-g-PP increased the peeling strength from 180 g/15 mm to 250 g/15 mm. 1-Decene inhibited the chain scission behavior of PP. 1-Decene reacted with MAH to form a 1-decene/MAH copolymer or the Alder-ene reaction product before the two monomers grafted onto PP. The grafting of the reactive product onto PP greatly improved the grafting degree of MAH. What is more, because of the similar chemical structures of 1-decene and PP, the affinity of 1-decene with PP was higher than that of St. Compared with St, the introduction of less 1-decene led to a higher grafting degree and higher peeling strength. Therefore, we concluded that 1-decene was more effective for improving the grafting degree of MAH onto PP. © 2010 Wiley Periodicals, Inc.
Huang X.,Shanghai JiaoTong University |
Wei W.,Shanghai JiaoTong University |
Wei H.,Shanghai JiaoTong University |
Li Y.,King Fa Science and Technology Co. |
And 2 more authors.
Journal of Applied Polymer Science | Year: 2013
An amine-terminated curing agent for epoxy resin based on hexachlorocyclotriphosphazene was synthesized. Its chemical structure was characterized by1H-NMR, FT-IR, and elemental analysis. The curing temperature was determined by differential scanning calorimeter. The thermal stability, hydrophobicity, flame retardancy, and insulation property of the epoxy resin cured by the as-prepared curing agent were superior to those of the epoxy resin cured by 4,4-diaminodiphenylsulfone. The epoxy resin cured by the new curing agent obtained the best heat-moisture resistance when the ratio of amino protons and epoxy group was 1.2: 1. The temperature reached 318 and 376°C when the weight loss was 5 and 10% meanwhile the residue at 800°C was above 64%. The material achieved UL94 V-0 rating and the water absorption was only 0.57%. The electric insulation property was also improved especially when it was compared in wet conditions at water absorption saturation. © 2013 Wiley Periodicals, Inc.
Gao H.,Nankai University |
Gao H.,Kingfa Science and Technology Company |
Cheng T.,Nankai University |
Liu J.,Peking Union Medical College |
And 5 more authors.
Biomacromolecules | Year: 2014
Exploring ideal nanocarriers for drug delivery systems has encountered unavoidable hurdles, especially the conflict between enhanced cellular uptake and prolonged blood circulation, which have determined the final efficacy of cancer therapy. Here, based on controlled self-assembly, surface structure variation in response to external environment was constructed toward overcoming the conflict. A novel micelle with mixed shell of hydrophilic poly(ethylene glycol) PEG and pH responsive hydrophobic poly(β-amino ester) (PAE) was designed through the self-assembly of diblock amphiphilic copolymers. To avoid the accelerated clearance from blood circulation caused by the surface exposed targeting group c(RGDfK), here c(RGDfK) was conjugated to the hydrophobic PAE and hidden in the shell of PEG at pH 7.4. At tumor pH, charge conversion occurred, and c(RGDfK) stretched out of the shell, leading to facilitated cellular internalization according to the HepG2 cell uptake experiments. Meanwhile, the heterogeneous surface structure endowed the micelle with prolonged blood circulation. With the self-regulated multifunctional collaborated properties of enhanced cellular uptake and prolonged blood circulation, successful inhibition of tumor growth was achieved from the demonstration in a tumor-bearing mice model. This novel nanocarrier could be a promising candidate in future clinical experiments. © 2014 American Chemical Society.
Tao W.,Tsinghua University |
Zeng X.,Tsinghua University |
Liu T.,Tsinghua University |
Wang Z.,Tsinghua University |
And 4 more authors.
Acta Biomaterialia | Year: 2013
A star-shaped biodegradable polymer, mannitol-core poly(d,l-lactide-co- glycolide)-d-α-tocopheryl polyethylene glycol 1000 succinate (M-PLGA-TPGS), was synthesized in order to provide a novel nanoformulation for breast cancer chemotherapy. This novel copolymer was prepared by a core-first approach via three stages of chemical reaction, and was characterized by nuclear magnetic resonance, gel permeation chromatography and thermogravimetric analysis. The docetaxel-loaded M-PLGA-TPGS nanoparticles (NPs), prepared by a modified nanoprecipitation method, were observed to be near-spherical shape with narrow size distribution. Confocal laser scanning microscopy showed that the uptake level of M-PLGA-TPGS NPs was higher than that of PLGA NPs and PLGA-TPGS NPs in MCF-7 cells. A significantly higher level of cytotoxicity was achieved with docetaxel-loaded M-PLGA-TPGS NPs than with commercial Taxotere®, docetaxel-loaded PLGA-TPGS and PLGA NPs. Examination of the drug loading and encapsulation efficiency proved that star-shaped M-PLGA-TPGS could carry higher levels of drug than linear polymer. The in vivo experiment showed docetaxel-loaded M-PLGA-TPGS NPs to have the highest anti-tumor efficacy. In conclusion, the star-like M-PLGA-TPGS copolymer shows potential as a promising drug-loaded biomaterial that can be applied in developing novel nanoformulations for breast cancer therapy. © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Jiang H.,Southwest Jiaotong University |
Cheng Q.,Southwest Jiaotong University |
Jiang C.,Southwest Jiaotong University |
Zhang J.,Southwest Jiaotong University |
Yonghua L.,Kingfa Science and Technology Co.
Tribology International | Year: 2015
For the scratch process of polypropylene (PP), the stick-slip phenomenon always exists and contributes to the observed periodic surface damage patterns. The stick-slip, one main cause for scratch visibility, alters the surface characteristics of substrate and eventually induces scratch visibility. Both ASTM/ISO and Erichsen scratch test methods are employed to study the stick-slip phenomenon and its effects on scratch behavior of PP. Image analysis shows that the stick-slip phenomenon was responsible for material removal and severe surface damage. Possible solutions to improve the scratch performance of polymeric materials are also discussed in this paper. © 2015 Elsevier Ltd. All rights reserved.
He J.-H.,South China University of Technology |
He J.-H.,Kingfa Science and Technology Co. |
Zhao J.-Q.,South China University of Technology
Gaofenzi Cailiao Kexue Yu Gongcheng/Polymeric Materials Science and Engineering | Year: 2010
By the methods of limited oxygen index (LOI), cone calorimeter, Fourier transform infrared spectroscopic(FT-IR), scanning electron microscope (SEM) and wide angle X-ray diffraction (WAXD), the synergistic flame-retarding property and mechanism of a silicon-containing flame retardant (SFR-H) and ammonium phosphate/melamine cyanurate (APP/MCA) intumescent flame-retardant system were studied. The results imply that SFR-H/APP/MCA synergistic flame-retarding system obviously improves the LOI value and decreases heat release rate of linear low density polyethylene (LLDPE) during combustion. SFR-H exhibits good synergistic flame-retarding effect with APP/MCA intumescent flame-retardant system. They degraded to generate ceramic compounds containing silicon, boron and phosphorus elements during combustion, which improves the flame-retarding effect by reinforcing the thermo-oxidative stability, mechanical property and insulating effect of continuous intumescent charred layer.
Ke F.,Donghua University |
Jiang X.,Donghua University |
Xu H.,Donghua University |
Ji J.,Kingfa Science and Technology Co. |
Su Y.,Kingfa Science and Technology Co.
Composites Science and Technology | Year: 2012
The binary nano-CaCO 3/polypropylene (PP), poly(ethylene terephthalate) (PET) fibers/PP and ternary nano-CaCO 3/PET fibers/polypropylene composites were prepared by melt blending method, and their structure and mechanical properties were investigated. The results show that the ternary nano-CaCO 3/PET fibers/PP composite displays significantly enhanced mechanical properties compared with the binary PET fibers/PP and nano-CaCO 3/PP composites, and neat PP. The X-ray diffraction, dynamic mechanical analysis, scanning electron microscopy and analysis of the non-isothermal crystallization kinetics were used to investigate the reinforcement mechanism of composites. The results indicate that the interfacial action and compatibility between PET fiber and PP are obviously enhanced by the addition of modified nano-CaCO 3 particles in the ternary composites and the mechanical property enhancement in the ternary system may be mainly originated from the formation of β-form crystallites of PP induced by the synergistic effect between PET fibers and nano-CaCO 3.. © 2012.
Xiong K.,Kingfa Science and Technology Co. |
Wang L.,South China University of Technology |
Cai T.,Kingfa Science and Technology Co. |
Zhang A.,South China University of Technology |
Zeng X.,Kingfa Science and Technology Co.
Polymer Bulletin | Year: 2012
POE-graft-methyl methacrylate and acrylonitrile (POE-g-MAN) was prepared by suspension graft copolymerization of methyl methacrylate (MMA) and acrylonitrile (AN) onto polyethylene-octene copolymers (POE). POE-g-MAN/SAN resin blends (AOMS) were prepared by blending POE-g-MAN with styrene-acrylonitrile copolymer (SAN resin). The effects of reaction conditions on the graft copolymerization and the toughening effect of POE-g-MAN on SAN resin were discussed. The results showed that the optimized reaction conditions were AN/(MMA + AN) ratio of 15 wt%, POE/(POE + MM - AN) ratio of 60 wt%, BPO/(POE + MMA - AN) ratio of 1 wt%, toluene dosage of 44.4 wt%, PVA dosage of 0.4 wt%, SDS dosage of 0.07 wt%, aqueous phase/oil phase mass ratio of 1.5, at 80 °C for 20 h, and when the POE/AOMS mass ratio was 25 wt% under the optimized reaction conditions, the notched Izod impact strength of AOMS reached 54.0 kJ/m 2. Fourier transform infrared spectroscopy provided substantial evidence of grafting of MMA and AN onto POE chains, and differential scanning calorimetry showed that the graft branches affected the crystallization of POE chains and made the melt temperature and the fusion heat be lower. Transmission electron microscopy analysis showed that the highest toughness occured when the size of POE-g-MAN particles and the surface to surface interparticle distance were proper. Scanning electron microscopy analysis indicated that the AOMS fracture surface had plastic flow visible which looked like a fibril morphology when POE content was 25 wt% with the AN/(MMA + AN) ratio (f AN) of POE-g-MAN of 15 wt%. The toughening mechanism of AOMS was shear yielding of matrix, which endowed AOMS with remarkable toughness. Dynamic mechanical thermal analysis showed that the compatibility of the POE phase and SAN phase improved after graft copolymerization of MMA and AN onto POE. © 2012 Springer-Verlag.
Kingfa Science, Technology. Co. and Shanghai Kingfa Science & Technology Co. | Date: 2014-12-17
Disclosed are a halogen-free fire-retardant polyamide composition, and a preparation method and application thereof. The halogen-free fire-retardant polyamide composition is prepared from 35 to 71.5% of a semi-aromatic polyamide, 10 to 35% of a fire retardant and 0 to 50% of an inorganic reinforcing filler, the terminal amino group content of the semi-aromatic polyamide being 80 to 150 mol/t. The halogen-free fire-retardant polyamide composition of the present invention has good heat stability and releases only a small amount of gas in production; mold dirt is not easily formed, and the halogen-free fire-retardant polyamide composition can be produced continuously.