Time filter

Source Type

Yan H.,Zhejiang University | Wang H.,Zhejiang Textile and Fashion Technology College | Fang Z.,Zhejiang University
Industrial and Engineering Chemistry Research | Year: 2014

Flame retardant ramie/benzoxazine resin laminates were prepared and modified by ammonium polyphosphate (APP) and a nitrogen-phosphorus flame retardant (NEWRAY911). The results showed that the limiting oxygen index (LOI) values of the ramie/benzoxazine laminates could be ameliorated by the addition of APP, but did not achieve V0 level in UL94 test. Their mechanical strengths were also partially damaged. To improve the flame retardancy and reduce the mechanical damage to laminates, ramie fabric was modified by NEWRAY911 before compounding. The LOI value of the laminate made by flame retardant ramie fabric could be increased to 44.8%, and the laminates achieved V0 level in UL94 test. Compared to the unmodified laminates, the flame retarding modification of the fabric helped to improve the mechanical properties of laminates. The mechanism of flame retardancy of these laminates was investigated further by thermogravimetric analysis coupled with infrared spectroscopy, microscale combustion calorimetry measurements and scanning electron microscopy. © 2014 American Chemical Society. Source

Yan H.,Zhejiang University | Wang H.,Zhejiang Textile and Fashion Technology College | Cheng J.,Zhejiang University | Fang Z.,Zhejiang University
Gaofenzi Cailiao Kexue Yu Gongcheng/Polymeric Materials Science and Engineering | Year: 2011

Bismaleimide containing ether linkage and naphthalene (BMPN) was synthesized from 2, 7-dihydroxynaphthalene and p-chloronitrobenzene by four-step method. The monomer of bismalemide was characterized by Fourier transform infrared spectrum(FT-IR) and 1H nuclear magnetic resonance spectrum(1H-NMR). The thermal stability of BMPN resin was studied by thermogravimetry(TG) measurements at a heating rate of 10°C/min in N2. The results indicate that Te of BMPN rsin is 477.1°C and the anaerobic char yield is 63.8% at 700°C. It is illuminated that introduction of naphthalene can make up the loss of thermal properties due to the introduction of ether linkage and increases the anaerobic char yield at 700°C. Compared to BMP resin, thermal degradation rate of BMPN resin decreases. Source

Yan H.,Zhejiang University | Wang H.,Zhejiang Textile and Fashion Technology College | Cheng J.,Zhejiang University | Fang Z.,Zhejiang University
Advanced Materials Research | Year: 2011

To obtain attractive properties, such as increased resistance to moisture absorption, low dielectric constant and low dielectric loss, the novel bismaleimide, viz. 2,7-bis(4-maleimidophenoxy) naphthalene (BMPN), and dicyanate ester, viz. 2,7-dihydroxynaphthalene dicyanate (DNCY), containing naphthalene ring and ether linkages, have been synthesized. The cure process of the blends including of 0.11mmol/mol Fe(AcAc)3 and 2% nonylphenol is characterized by in-situ FTIR. The result obtained from in-situ FTIR spectra of cured resin illuminates that the cure reaction is homo-polymerized respectively at this condition for the mixtures of B1C1. Interlaced network patterns are seen obviously and no visible phase separation could be detected in the region for IPNs BT resin by SEM. The structure of IPNs can be formed for the blends of BMPN and DNCY containing 0.11 mmol/mol Fe(AcAc)3 and 2% nonylphenol, which is tested by in-situ FTIR and SEM methods. The glass fiber reinforced composites for this blends are made and their properties are studied. This composites show good flexural property, low dielectric constants ( Dk ) and low moisture absorption. © (2011) Trans Tech Publications, Switzerland. Source

Lu X.,Zhejiang University | Yan H.,Zhejiang University | Wang H.,Zhejiang Textile and Fashion Technology College | Cheng J.,Zhejiang University | Fang Z.,Zhejiang University
Fuhe Cailiao Xuebao/Acta Materiae Compositae Sinica | Year: 2011

The ramie fabric was treated with two different types of flame retardants, namely phosphate type and nitrogen-phosphorous type, and composed with phenolic resin to prepare ramie/phenolic resin laminate. The flame retardancy of the laminate treated by nitrogen-phosphorous type flame retardant is better than that treated by phosphate type flame retardant. The limiting oxygen index (LOI) of the laminate with nitrogen-phosphorous type treatment increases from 25.2% to 39.1%, and reaches the V0 level in UL94 vertical burning test, while LOI of the laminate with the phosphate type treatment only increases to 27.8%. Cone calorimeter tests show that the laminates with the nitrogen-phosphorous type treatment have increased char residue, extended ignition time and decreased peak heat release rate and average smoke density. It is also found that the mechanical properties of the laminates are not changed because of the little damage on the fiber structure of ramie fabric with the flame retardant treatment. Source

Yan H.-Q.,Zhejiang University | Wang H.-Q.,Zhejiang Textile and Fashion Technology College | Cheng J.,Zhejiang University | Fang Z.-P.,Zhejiang University
Gao Xiao Hua Xue Gong Cheng Xue Bao/Journal of Chemical Engineering of Chinese Universities | Year: 2011

The cure reaction and thermal properties of bismaleimides containing ether linkage were characterized by methods of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It shows that the cure reaction and thermal properties of BMPN are obviously different from those of BMPB and BMPA because of the existence of naphthalene in the structure of bismaleimide (BMI) resin forming BMPN. The cure reactive activation of -C=C- group in the structure of BMPN is lower than those in the structures of BMPB and BMPA because of stronger electro-attracting ability of naphthalene ring in BMPN, and the activation energy for cure reaction of BMPN (117.7 kJ · mol -1) is higher than those of BMPB and BMPA. The thermal and thermal-oxidative stabilities of BMPN are ameliorated obviously due to the introduction of naphthalene ring in its BMI resin, and the introduced naphthalene ring plays a more important role towards the thermal-oxidative stability than the thermal stability. The existence of aromatic ring leads to reduce the rates of thermal and thermal-oxidative decompositions during high temperature stage. Compared to BMP resin, introduction of naphthalene ring remedies the loss of thermal and thermal-oxidative stability caused by the introduction of ether linkage. Source

Discover hidden collaborations