新型成炭剂对PE-LD阻燃性能的影响

以多聚磷酸铵（APP）与新型成炭剂（CNCH-DA）复配成新型膨胀型阻燃剂（IFR）,采用氧指数测定仪、垂直燃烧测定仪、微型量热仪、热重分析仪和扫描电子显微镜研究了CNCH-DA 对低密度聚乙烯（PE-LD）/IFR复合材料阻燃性能的影响。结果表明,当APP与CNCH-DA以质量比5:1复配时,PE-LD/IFR复合材料的极限氧指数达到27.5 %,且达到UL 94 V-0级;当APP与CNCH-DA复配后,PE-LD的燃烧性能下降;APP与CNCH-DA复配后,PE-LD/IFR复合材料的热降解有所推迟;PE-LD/IFR在燃烧后能形成致密且蓬松的炭层,起到良好的阻燃效果,而PE-LD/CNCH-DA则形成蓬松而不致密的微球,阻隔能力差。     

FeCrSiB合金的激光熔敷

应用千瓦级 CO_2激光器对 A_3钢上的 Fe 基热喷涂层进行熔敷处理,用金相、x 射线衍射、扫描电镜、透射电镜、硬度、磨损、声发射及电化学等方法研究了熔敷层的组织与性能。结果表明:激光熔敷消除了热喷涂层的不致密性缺陷,使涂层与基材实现冶金结合。激光熔层组织显著细化,成分均匀,消除了大块碳化物偏析,呈现尺寸1～2 μm 的胞状晶快冷组织。其相组成为α′-Fe+γ-Fe+M_7C_3+M_(23)C_6+F_2B。激光熔敷产生的多种强化机制使涂层的硬度、耐磨性、脆性、强度及耐腐蚀性有了显著提高,从而在低廉的钢材上获得性能优异的表面。是一种有实用价值的激光熔敷技术。     

内燃机火焰平均传播时间的测量电路设计

本文论述了内燃机N个连续循环中火焰平均传播时间的测量原理,设计了相应的测量电路,讨论了提高测量精度的方法,因而给内燃机动态测试提供了一种新的有效方法,同时亦给其它各种机构时间特性的分析测量提供了一种新的简单方法。     

Effect of Functionalized Graphene with Modified Clay on Flammability of Copper Clad Laminated Novolac Cured Epoxy Composites

In this work, we prepared epoxy composites and a copper clad laminates (CCLs) by an introduction of modified clay with graphene to a novolac cured epoxy resin to improve the thermo-mechanical and flame retardant properties. Further, the typical important properties of synthesized CCLs were investigated. The incorporation of surface modified organographene (OG) and organomodified clay with suitable concentration can noticeably increase the storage modulus, crystallinity, the heat distortion temperature, and flame retardant of the CCLs. Moreover, these results suggest the potential of the epoxy composites for the printed circuit such as high speed IC boards.     

勃姆石改性PET复合材料的阻燃和增强机理研究

采用勃姆石（BM）作为阻燃和增强材料,利用熔融共混法制备了BM阻燃和增强改性的聚对苯二甲酸乙二醇酯（PET）/BM复合材料。分别测试了BM用量对于PET复合材料的力学性能、结晶性能、热性能、阻燃性能的影响。结果表明,随着BM用量的增加,PET/BM复合材料的刚性逐渐增加,韧性逐渐降低;PET/BM复合材料的热结晶温度（Tc）和冷结晶温度（Tcc）分别随着BM用量的增加逐渐升高和降低,且ΔT(Tc-Tcc)逐渐增加,BM具有异相成核作用,提高了复合材料的结晶速率和相对结晶度（Xc）;而复合材料的熔融温度则随着BM用量的增加而逐渐降低;BM对PET具有良好的阻燃作用,BM能够使PET/BM复合材料的残炭量增加,使复合材料的分解温度降低,增加了材料燃烧时的热稳定性。     

机械力化学制备锡酸锌及其在PVC中的阻燃应用

以二氧化锡（SnO₂）和氧化锌（ZnO）为原料,通过机械力化学湿法球磨,制备了锡酸锌（ZS）,再与水滑石按一定比例研磨得到锡酸锌改性的水滑石（ZS/HT）。通过扫描电子显微镜、X射线衍射、透射电子显微镜对合成的ZS与ZS/HT做了表征。将制得的ZS/HT应用于PVC制得阻燃PVC样品,当加入10%（ZS与水滑石的质量比）ZS/HT时材料的极限氧指数比纯PVC样品高3.5%,同时材料的力学性能有所增加。热重分析结果表明,ZS/HT的加入促使PVC提前分解成炭,有效提高PVC材料的残炭量。     

双层涤纶汽车座套面料的阻燃性能研究

选用不同比例的阻燃涤纶和普通涤纶长丝,设计织造了8种双层小提花织物,同时对织物进行了阻燃性能测试。结果表明:1#织物为最优织物,其采用接结双层组织,表里层为质量比1∶1的阻燃涤纶和普通涤纶,织物中使用的阻燃涤纶比例高,阻燃涤纶覆盖率系数大,织物的烫穿时间长,阻燃效果好。与纯阻燃涤纶织物相比,1#织物不仅达到了相同的阻燃效果,还减少了阻燃涤纶的使用量,节约了成本。设计织造的8种织物的阻燃性能均达到汽车用纺织品的阻燃要求,可以供企业在大生产中应用。     

有色阻燃异径聚酯FDY热收缩率的探讨

以阻燃聚酯切片与高色牢度色母粒为原料,制备了有色阻燃异径聚酯全拉伸丝(FDY),重点探讨了工艺条件对其热收缩性能的影响。结果表明:在试验范围内,有色阻燃异径聚酯FDY的热收缩率较有色普通异径聚酯FDY的高;拉伸温度对有色阻燃异径聚酯FDY热收缩率的影响很小,而定形温度与纺丝速度对其影响较大,且有色阻燃异径聚酯FDY的热收缩率随定形温度的升高而下降,随纺丝速度的降低而降低。     

Synthesis of a novel DOPO‐based polyphosphoramide with high char yield and its application in flame‐retardant epoxy resins

A novel and highly effective flame retardant (FR), DOPO‐TPMP oligomer, was synthesized by a simple condensation of 4‐(hydroxymethyl)‐2,6,7‐trioxa‐1‐phosphabicyclo[2.2.2]octane‐1‐oxide and phosphorus oxychloride followed by a polycondensation reaction with 6‐(2,5‐dihydroxyphenyl)‐6H‐dibenzo[c,e][1,2]oxaphosphinine‐6‐oxide. The chemical structure of DOPO‐TPMP was well characterized using Fourier transform infrared and NMR spectra. DOPO‐TPMP was used as an additive‐type FR for epoxy resin (EP). The FR properties of the resultant EP composites were investigated by limiting oxygen index (LOI) test, UL‐94 vertical burning test and cone calorimeter measurements. Specifically, the EP composite containing 10.0% DOPO‐TPMP achieved a LOI value of 36.1%, V‐0 rating in the UL‐94 test and a 58% reduction in peak heat release rate. Further mechanism analysis attributed the enhanced flame retardancy to the increased char yield on the addition of DOPO‐TPMP. © 2019 Society of Chemical Industry     

Study on downward flame spread over extruded polystyrene foam in a vertical channel: Influence of opening area

Experimental methods and theoretical analysis are employed to investigate effects of channel opening area on downward flame spread characteristics of extruded polystyrene (XPS) thermal insulation materials on building facade. The average flame height first drops and then rises as dimensionless opening area (the ratio of sidewall opening area to sidewall area, ie, S^*) increases. As S^* rises, both the average and maximum temperature of the curtain wall decrease, and the decreasing of the average temperature is linear. XPS surface temperature history can be divided into four stages, ie, inapparent rising stage (preheating), significant rising stage (melting), dropping stage (pyrolysis), and rerising stage (ignition). The preheating length first rises and then drops as S^* increases. The XPS flame spreads steadily at the early period while acceleration occurs at the later period. For different opening areas, the difference in spread distance history is not apparent in the early stage while this difference is significant in the later stage. The flame spread rate (V_f) first increases and then decreases as S^* rises. A downward flame spread model for XPS in vertical channel with openings is built. The varied trend of V_f predicted using this model corresponds to the experimental result.