纳米改性氢氧化铝在PBT中的阻燃应用

首次采用纳米改性氢氧化铝（CG-ATH）对对苯二甲酸丁二醇酯（PBT）进行阻燃研究,考察了纳米（CG—ATH）的填充量对PBT／CG—ATH复合材料力学性能以及燃烧性能的影响。实验结果表明,随着CG-ATH填充量的增加,复合材料的拉伸强度、断裂伸长率和冲击强度都呈先上升后下降的趋势,在纳米CG-ATH填充量为5％时,冲击强度、断裂伸长率达到最大值,分别为5．0kJ／m^2和15．9％;在CG—ATH填充量达到15％时．拉伸强度达到最大值58．2MPa。纳米CG—ATH具有提高氧指数、降低分解速度的作用,但其分解产物具有促使炭残余物分解的负面作用。     

木质素填充改性SBS弹性体的性能

以玉米秸秆木质素为填充剂,利用溶液浇铸的方法制备了不同木质素填充的苯乙烯/丁二烯/苯乙烯嵌段共聚物(SBS)膜材料,借助力学性能测试以及动态力学分析(DMA)、锥形量热分析等手段,研究了木质素的填充对SBS力学性能和燃烧性能的影响。拉伸试验结果表明,木质素的填充能使SBS的力学性能提高,在木质素质量分数为6%时,SBS膜的拉伸强度可达到22.8MPa,断裂伸长率可达2400%,比未添加木质素时分别增加了32%和15%。DMA分析表明,木质素填充SBS后,弹性体的模量和玻璃化转变温度提高。锥形量热分析可以看出,木质素的添加降低了SBS燃烧过程中的总热释放量,并且使燃烧后的烟量减少;加入木质素后,SBS燃烧过程的质量损失变得缓慢,木质素的填充提高了SBS弹性体的阻燃性能。     

纳米改性氢氧化铝/尼龙66复合材料的制备及其力学性能的研究

将自制的纳米改性氢氧化铝(CG-ATH),用不同表面改性剂进行改性,以不同比例添加到PA66中,制得复合材料.该种复合材料的阻燃性能、拉伸性能和冲击性能都有所改善,纯尼龙66与添加40份CG-ATH/PA66复合材料相比较,极限氧指数(LOI)从25提高到29,拉伸性能提高了31%,冲击强度提高了8.6%.但是,随着CG-ATH添加量的增加,复合材料的阻燃性能和力学性能均逐渐变差.     

无机填料对低粘度高性能环氧树脂性能的影响

研究了空心玻璃微珠QH550、石英砂、氧化锌、白炭黑等无机填料对低粘度高活性环氧树脂体系的填充效果,通过比较树脂体系的拉伸性能、弯曲性能和冲击性等力学性能表明,用氧化锌作为填料时,树脂体系各项力学性能达到最优;研究了氧化锌的填充量对树脂体系力学性能的影响,找到了最佳填充量为树脂总质量的60%。     

空心玻璃微珠/环氧复合材料的制备及性能研究

制备了空心玻璃微珠/环氧复合材料。通过力学性能、固化收缩率、热性能等测试考察了空心玻璃微珠粒径、填充量、硅烷偶联剂处理对树脂及固化物性能的影响。结果表明,硅烷偶联剂改善了空心玻璃微珠与树脂基体的相容性。复合材料的力学性能随着空心微珠粒径减小而增大。随着空心微珠填充量的加大,固化物拉伸强度有所降低,冲击强度和弯曲强度在空心玻璃微珠质量分数为2%时达到最大值,比纯树脂分别提高了30%和34.2%,同时材料的固化收缩率和密度降低,玻璃化转变温度升高。     

聚苯硫醚/纳米Si3N4复合材料的制备及性能研究

表面改性处理的纳米Si3N4粉体与聚苯硫醚（PPS）熔融共混挤出制成PPS/纳米Si3N4复合材料,通过拉伸、冲击实验及动态力学性能测试考察了纳米粉体加入量对复合体系各项性能的影响。结果表明,纳米Si3N4填充PPS基复合材料的力学性能明显优于纯PPS。随粉体添加量的增加,复合材料的拉伸强度增大,当添加量为0.8 %时,拉伸强度提高了22 %。随粉体添加量的增加,复合体系冲击强度增大,当粉体添加量为1.2 %时,冲击强度和缺口冲击强度出现最大值,分别比纯PPS增加了33 %和41 %。动态力学性能测试表明,随粉体添加量的增加,PPS分子链段松弛所需能量增加,松弛过程增长,体系储能模量降低,损耗模量增加。     

m-ACR对PVC/木粉复合材料力学性能的影响

采用乳液聚合的方法合成了反应性核壳结构丙烯酸酯类抗冲击改性剂(m-ACR),使用双辊开炼机制备了聚氯乙烯(PVC)/椴木粉(WF)/m-ACR复合材料。通过力学性能测试和扫描电镜分析表明,m-ACR复合材料体系的力学性能得到提高,木粉与PVC界面结合性能得到改善,m-ACR的添加量为9 phr时,m-ACR体系的拉伸强度较未改性ACR体系的拉伸强度提高了8.74%;与ACR相比m-ACR增韧PVC效率略有降低,添加量为10 phr时冲击强度较PVC/WF体系提高了208%;动态力学分析表明,m-ACR加入后,复合材料体系的黏度增大,玻璃化温度增加。     

SiC颗粒增强不饱和聚酯树脂复合材料的力学性能

采用万能试验机和硬度计测试研究了SiC颗粒含量和粒径对不饱和聚酯树脂基复合材料力学性能的影响,通过扫描电子显微镜观察了拉伸试样的端口形貌。结果表明,填充的SiC质量分数为10%时,其不饱和聚酯树脂复合材料拉伸强度达到最大,8000目、1000目SiC填充体系拉伸强度分别为53.2MPa,44.8MPa,较纯树脂体系提高68.1%,41.5%。当SiC质量分数为30%时,SiC填充体系的弹性模量较纯树脂体系提高25.8%以上,硬度提高2.3%以上,SiC颗粒尺寸对复合材料的弹性模量和硬度影响不大。SiC/不饱和聚酯树脂复合材料的断裂属脆性断裂。     

反应性聚醚砜对RTM用6421BMI树脂性能的影响

通过SEM及力学性能测试,研究了反应性聚醚砜(rPESU)用量对6421BMI树脂性能的影响,结果表明,rPESU能够显著提高6421树脂的冲击韧性,当rPESU质量分数达到10%时,rPESU在6421树脂中形成连续相,质量分数达到15%时,6421树脂的冲击强度值最高,为纯6421树脂的5倍。rPESU的加入量对6421树脂拉伸模量、压缩模量、弯曲模量的影响很小,但6421树脂的拉伸强度和弯曲强度随rPESU用量增加降低很快,rPESU质量分数达到25%时,拉伸强度和弯曲强度值降为原来的50%左右。     

PP-硅橡胶-LLDPE三元共聚物的合成及性能研究

以聚丙烯(PP)为基体树脂,硅橡胶为增韧剂,线性低密度聚乙烯( LLDPE)为辅增韧剂,制备了一系列的PP/硅橡胶LLDPE的三元共聚物,考察了PP填充不同配比的硅橡胶共混物的力学性能.结果表明,随着硅胶含量不断的增加,样条的断裂伸长率,弹性模量,冲击强度逐渐增加,样条的拉伸强度随着硅胶的增加而逐渐减少;LLDPE的加入量为15％时,PP/硅橡胶/LLDPE的三元共混体系力学性能最佳;硅橡胶的加入量为20％时,PP/硅橡胶/LLDPE的三元共混体系具有良好的拉伸性能和冲击强度.     

Effect of the particle size of expandable graphite on the thermal stability,flammability, and mechanical properties of high‐density polyethylene/ethylene vinyl‐acetate/expandable graphite composites

In this article, high‐density polyethylene/ethylene vinyl‐acetate copolymer (HDPE/EVA) composites filled with two different particle sizes (45 and 150 µm) of expandable graphite (EG) were prepared by using a twin‐screw extruder. The thermal stability, flammability, and mechanical properties of HDPE/EVA/EG composites were investigated by thermogravimetric analysis (TGA), cone calorimeter test (CCT), tensile test, and scanning electron microscopy (SEM). The results from TGA and CCT indicated that EG significantly enhanced the thermal stability and fire resistance of HDPE/EVA blend. The thermal stability and flame retardancy of HDPE/EVA/EG composites were improved with decreasing particle size of EG. Although the onset of weight loss of the flame‐retardant composites occurred at a lower temperature than that of HDPE/EVA blend, the flame‐retardant composites produced a large amount of char residue at a high temperature. The consolidated char layer formed a barrier, which could reduce heat, low‐molecular transfer, and air incursion, and thus enhanced the flame retardancy. The data from the tensile test showed that the addition of EG deteriorated the mechanical properties; however, the tensile stress and strain of HDPE/EVA/EG composites increased with decreasing the particle size of EG owing to the strong interface adhesion between polymer matrix and inorganic particles. POLYM. ENG. SCI., 54:1162–1169, 2014. © 2013 Society of Plastics Engineers     

A novel intumescent flame retardant-functionalized montmorillonite: Preparation,characterization, and flammability properties

2,4,8,10-Tetraoxa-3,9-diphosphaspiro[5.5]-undecane-3,9-dioxide-disubstitutio-acetamide-N,N-dimethyl-N-hexadecy-ammonium bromide (PDHAB) containing phosphorus–nitrogen structure was synthesized and characterized. A novel flame retardant, montmorillonite (Mt) modified by PDHAB (PDHAB-Mt), was prepared by ion-exchange of sodium montmorillonite (Na⁺-Mt) with PDHAB. The results of X-ray diffraction (XRD) indicated that PDHAB had intercalated with Na⁺-Mt and exfoliated LDPE/EVA/20% PDHAB-Mt nanocomposites had been obtained by polymer melt intercalation which was further supported by TEM. The flammability of LDPE/EVA/PDHAB-Mt nanocomposites was investigated by the cone calorimeter test. The results showed that the addition of flame retardant PDHAB-Mt enhanced the flame retardancy of LDPE/EVA blend significantly. The results of SEM and TEM indicated that PDHAB-Mt can achieve better dispersion in the chars after combustion and the intumescent char is formed for LDPE/EVA/PDHAB-Mt nanocomposites after combustion. It is found that the char structure plays an important role for PDHAB-Mt in LDPE/EVA blend. The flame retardancy of LDPE/EVA blend was also significantly improved by an addition of PDHAB-Mt in LDPE/EVA blend.     

Studies on effect of nanoclay on the properties of thermally sprayable EVA and EVAI coatings

Dispersion of nanoclay (NC) in polymer blend system is governed by the sequence of addition of different ingredients. In the present work nanoclay was added in different sequences to blend composition such as ethylene vinyl acetate (EVA)/low density polyethylene (LDPE) and ethylene vinyl alcohol (EVAl)/LDPE in internal mixer to get nanocomposite. It was found that sequential addition of individual polymers and nanoclay influenced mechanical properties of resulting composites. Blending sequence of PE/NC/EVA and PE/NC/EVAl gave best mechanical properties. After optimization of addition sequence, concentration of nanoclay was varied from 1 to 8% by weight in the polymer blend. The resulting composites were evaluated in terms of their mechanical properties, dispersion characteristics (XRD), water vapor transmission rate (WVTR) and water absorption (Wa). Nanocomposite containing EVA/LDPE blend with 4% nanoclay showed optimum properties. The optimized composition was applied on grit blasted mild steel specimens by flame spray technique. The coated specimens were evaluated for adhesion strength, abrasion resistance and resistance to corrosion properties.     

HDPE/EVA/LDPE共混物拉伸性能和流变性能研究

用ＥＶＡ、ＬＤＰＥ、ＣａＣＯ３改性,填充ＨＤＰＥ,研究了它们的用量,品种对共混珠拉伸性能和流变性能的影响。结果表明,共混物熔体为假塑性流体。ＥＶＡ、ＬＤＰＥ用量增加,共混物拉伸强度下降,但断裂伸长率和熔体流动性提高。     

TPS/EVA泡沫复合材料的制备及其阻燃与力学性能

以热塑性淀粉(TPS)为成炭剂与聚磷酸铵(APP)、可膨胀石墨(EG)复配组成膨胀型阻燃剂,通过熔融密炼、开炼塑化、硫化发泡制备了热塑性淀粉/乙烯-醋酸乙烯酯共聚物(TPS/EVA)泡沫复合材料,探讨了TPS用量对泡沫复合材料阻燃性能、力学性能的影响。结果表明,TPS的加入显著提高了TPS/EVA泡沫复合材料阻燃性能,可起到良好的成炭作用;TPS/EVA泡沫复合材料的拉伸强度、断裂伸长率以及撕裂强度随着TPS用量的增加呈现先增大后减小的趋势,相对密度则是小幅度上升。当TPS用量为6%时,TPS/EVA泡沫复合材料综合性能最好,其LOI可达26.5%且UL-94为V-0级,拉伸强度、断裂伸长率、撕裂强度以及相对密度可达2.395 MPa、177.48%、10.59 N·mm^-1、0.21452。     

碱式硫酸镁晶须阻燃LDPE/EVA复合材料的研究

通过双螺杆挤出机制备了聚乙烯/聚乙烯-醋酸乙烯酯/碱式硫酸镁晶须(LDPE/EVA/MHSH)复合材料,氧指数、UL-94垂直燃烧、锥形量热实验和热重分析表明,MHsH能有效提高材料的阻燃性能和热稳定性.力学性能测试表明,MHSH对聚合物具有一定的增强作用.     

Effect of OMMTs on flame retardancy and thermal stability of poly(ethylene‐co‐vinyl acetate)/LDPE/magnesium hydroxide composites

The aim of this study was to prepare poly (ethylene‐co‐vinyl acetate) (EVA)/ low density polyethylene (LDPE)/magnesium hydroxide (MH) composites applicable in cable industry with required flame retardancy. For this reason, two types of organo‐modified montmorillonites (OMMT) with different surface polarites (Cloisite 15A and Cloisite 30B) at various concentrations, and also combination of these two OMMTs with overall loadings of 2 wt % and 5 wt % were used. The samples were compounded using a twin screw extruder with total (MH + OMMT) feeding of 55 wt % and 60 wt %. Limiting oxygen index (LOI) of the samples containing 2 wt % of OMMTs increased about 16% and dripping was suppressed according to vertical burning test (UL‐94V). Thermogravimetric results of EVA/LDPE/MH samples containing OMMT showed that the beginning of second step degradation was shifted about 50°C to higher temperatures. The composite tensile strength results showed enhancement by incorporating some amount of nanoclays with EVA/LDPE/MH composites. Scanning electron microscopy images confirmed that MH particles had better wetting by EVA matrix in presence of nanoclays. Oxidative induction time of the EVA/LDPE/MH/OMMT nanocomposites was 140 min, which was more than that of the samples without OMMT (20 min). Employing the equal weight ratios of the two OMMTs demonstrated a synergistic effect on flame retardancy of the samples according to the both tests results (LOI, UL‐94V). X‐ray diffraction analysis of the samples confirmed the intercalation/semiexfoliation structure of nanosilicate layers in the bulk of EVA/LDPE matrix. This led to longer elongation at break and thermal stability of Cloisite 15A based nanocomposites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40452.     

Preparation and properties of modified aluminum diethylphosphinate flame retardant for low-density polyethylene

To improve the flame retardancy of low-density polyethylene (LDPE) and mechanical properties of LDPE composites, phenol-formaldehyde aluminum diethylphosphinate microcapsules (PF@ADP) was prepared by in-situ polymerization with phenol-formaldehyde (PF) resin as the wall material and halogen-free flame-retardant aluminum diethylphosphinate (ADP) as the core material. The effects of PF@ADP on flame retardancy and mechanical properties of LDPE were investigated by methods of combustion experiments, mechanical analysis, thermogravimetric analysis (TGA), and smoke density analysis. The results indicated that, compared with ADP/LDPE composites, the flame retardancy and mechanical properties of PF@ADP/LDPE were obviously improved. With the addition of 20 wt% PF@ADP (PF:ADP = 3:7), the limit oxygen index (LOI) of LDPE composites increased to 30.7% and UL-94 reached V-1 grade. The tensile strength and elongation at break reached 12.5 MPa and 431.2%, which was 20.2% and 23.1% higher than that of ADP/LDPE with the same addition. The addition of PF@ADP was beneficial to the smoke suppression of LDPE.     

聚磷酸铵/氢氧化镁复配填充阻燃硅橡胶的研究

分别采用聚磷酸铵（APP）、氢氧化铝（ATH）和APP/ATH复配阻燃剂填充甲基乙烯基硅橡胶,制成阻燃型硅橡胶。研究了APP、ATH和APP/ATH用量及复配方式对硅橡胶阻燃性能、介电性能和力学性能的影响。结果表明,硅橡胶的阻燃性能随APP、ATH用量的增加而增加,同等填充量下,APP/ATH复配阻燃剂填充硅橡胶的阻燃性能比单一APP或ATH填充硅橡胶更佳;随着APP/ATH复配阻燃剂用量的增加,硅橡胶的拉伸强度与拉断伸长率降低,邵尔A硬度、介电常数和介质损耗因数增加。当100份硅橡胶中加入80份APP/ATH复配阻燃剂（APP与ATH的质量比为3∶2）时,硅橡胶的氧指数达44%,拉伸强度、拉断伸长率、邵尔A硬度、介电常数及介质损耗因数分别为6.8 MPa、438%、62度、3.92、249%。