发展阻燃型HIPS纳米复合材料的研究

本文运用一步熔融共混法制备了含有十溴联苯醚（DBDPO）或十溴二苯乙烷（DBDPE）和C16改性蒙脱土（MMT）的高抗冲聚苯乙烯（HIPS）复合材料,并采用X射线衍射（XRD）、透射电镜（TEM）、UL 94垂直燃烧和锥型量热等试验手段对其燃烧性能和相态进行了表征.结果标明,DBDPO/E存在时仍可获得具有插层结构的HIPS纳米复合材料.由于十溴和蒙脱土两种体系间的良好协同效应,这些材料的阻燃性提高、燃烧后的热释放速率下降.文中对其潜在机理进行了探讨.这种协同效应可用于指导发展环保性和阻燃性兼顾的HIPS纳米复合材料.     

纳米LDHs阻燃剂与氯化石蜡协效阻燃PS的性能与机理研究

文采用氧指数（LOI）测试结果讨论了纳米LDHs对PS,以及纳米LDHs与氯化石蜡协效阻燃剂对PS的阻燃作用。结果表明。在100份PS中加入80份LDHs时．复合材料的最高LOI可达28;而在100份PS中添加30份纳米LDHs后。再添加10份氯化石蜡时．复合材料LOI可达29．5．两者具有明显协效阻燃作用。并通过FT—IR和XPS测试结果分析了纳米LDHs与氯化石蜡的协效阻燃机理。研究发现,氯化石蜡热释放出HCl是其与纳米LDHs发生协同反应的关键。     

纳米混杂Kevlar／Surlyn复合材料的制备与防刺性能研究

本文介绍采用热压成型工艺制备纳米SiO2混杂Kevlar／Surlyn复合材料,研究了纳米粒子混杂工艺、纳米粒子含量对复合材料动态防刺性能的影响。结果表明,采用喷涂工艺制备的纳米SiO2混杂Kevlar／Surlyn复合材料可改善复合材料的防刺性能,其中纳米SiO2的含量为5wt．％时,复合材料的防刺效果最佳。     

纳米材料对健康的影Ⅱ噍

纳米材料是指物质结构在三维空间中至少有一维处于纳米尺度（1nm-100nm,1nm=10^-9m）或由具有纳米尺度结构特征的物质单元（包括稳定的团簇或人造原子团簇、纳米晶、纳米颗粒、纳米管、纳米棒、纳米线、纳米单层膜及纳米孔等）构成的且具有特殊性质的材料。     

构造材料对芳砜纶滤料热尺寸稳定性的影响

为揭示芳砜纶复合滤料在高温条件下的热尺寸稳定性,对不同基布、不同复合材料对芳砜滤料热收缩率的影响进行试验研究.结果表明:芳砜纶滤料在250℃高温下具有优异的热尺寸稳定性,优于芳纶1313、聚四氟乙烯、聚苯硫醚、聚酰亚胺等高温滤料;增加芳纶1313、聚四氟乙烯基布层之后,滤料的热收缩率有所提高,在经向上表现更为明显,聚四氟乙烯基布滤料的热缩事要高于芳纶1313基布滤料;分别混合50％的芳纶1313和聚酰亚胺纤维之后,芳砜纶复合滤料的热收缩率进-步增大,在纬向上表现更为明显,聚四氟乙烯基布聚酰亚胺复合滤料的热收缩事高于芳纶1313基布芳纶1313复合滤料.这说明构造材料对芳砜纶复合滤料的热尺寸稳定性有重要影响,选用时既要考虑提升耐化学、力学、过滤性能,也要重视对热尺寸稳定性能的影响.     

聚乙烯醇/氧化石墨插层纳米复合材料的结构和热分析

制备了聚乙烯醇/氧化石墨插层纳米复合材料,并用X-射线衍射仪和高分辨电镜对其结构进行了表征.X-射线衍射仪和高分辨电镜的试验结果表明,氧化石墨和聚乙烯醇插层氧化石墨的层间距分别为0.89 nm和1.4nm.该纳米复合材料的热分析和热失重图说明,氧化石墨的加入有利于提高聚乙烯醇/氧化石墨纳米复合材料的玻璃化转变温度和氧化温度,同时也降低了其热释放速率.     

锆改性纳米TiO的光催化性能研究

用溶胶-凝胶法制备了锆改性纳米二氧化钛光催化剂，并用XRD、UV-vis、BET等测定技术对所制得的粉体试样进行了表征。同时以甲基橙及苯酚为模拟污染物，评价了改性后纳米二氧化钛的光催化性能，发现其光催化活性大大高于未改性二氧化钛粉体，并得出当n（Zr）／n（Ti）=5／300时，锆改性纳米二氧化钛样品的光催化活性最高。     

氢氧化镁/红磷对硅橡胶/黏土纳米复合物阻燃性能的研究

选用甲基乙烯基硅橡胶(MVMQ)和十六烷基三甲基溴化铵(C16BrN)改性的蒙脱土(OMMT)纳米复合材料为原料,以氢氧化镁/微胶囊化红磷(MH/MRP)为阻燃剂,以气相法白炭黑为补强剂,用熔融共混法制备了无卤阻燃MVMQ纳米复合材料。笔者采用XRD表征制备的MVMQ/OMMT纳米复合物的结构,用机械性能测试研究气相法白炭黑和OMMT对MVMQ的协效补强作用,通过极限氧指数、UL94 V垂直燃烧法、环境扫描电镜(ESEM)和热重分析(TG)等分析测试手段研究其燃烧性能和热性能,结合材料宏观燃烧性能的改变,推断OMMT和MH/MRP对MVMQ的阻燃作用机理。     

硫化纳米铁的制备及其对亚甲基蓝的去除

为克服纳米零价铁易团聚、易氧化、电子选择性差等缺陷,引入硫对纳米铁进行改性制备了硫化纳米铁复合材料(S-nZVI),并利用透射电子显微镜(TEM)、X射线衍射仪(XRD)和傅里叶红外光谱(FTIR)等方法对制备的S-nZVI进行表征,同时研究了其对水溶液中亚甲基蓝(MB)的去除效果。S-nZVI对MB的去除过程符合准二级反应动力学模型,吸附等温线符合Langmuir模型。当MB初始质量浓度为1000 mg/L时,S-nZVI对MB的饱和去除量可达242.06 mg/g。     

MPP协同MF@ADP阻燃低密度聚乙烯性能研究*

为提高低密度聚乙烯（LDPE）阻燃性能和阻燃LDPE复合材料的力学性能与抑烟性能,采用原位聚合法制备三聚氰胺-甲醛（MF）树脂包覆二乙基次磷酸铝（ADP）的MF@ADP微胶囊,再引入三聚氰胺聚磷酸（MPP）与MF@ADP进行协效复配,熔融共混制备阻燃LDPE复合材料。通过氧指数、热重分析、力学测试和烟密度测试等研究复合材料的阻燃、力学和抑烟性能。研究结果表明:MF@ADP微胶囊能改善阻燃剂与复合材料之间的相容性,与MPP复配构成的磷-氮膨胀阻燃体系能有效提高LDPE的抑烟性能;当MF@ADP∶MPP的质量比为2∶1时,材料的LOI达到了30.6%,垂直燃烧测试达到UL-94 V0级,拉伸强度为11.8 MPa,且形成的P/N/O高聚物炭层稳定性更高,可减少LDPE燃烧释放的烟雾量。     

聚碳酸酯/ABS/蒙脱土纳米复合材料的热重动力学分析

利用直接熔融插层技术制备聚碳酸酯/ABS聚合物合金/蒙脱土纳米复合材料.用热重分析法(TGA)研究了聚合物合金和纳米复合材料的热氧化降解行为.分别采用了无模式函数法(model-freemethod)和多元非线性回归法(multivariate nonlinearregression method)进行动力学评价.由此确定了整个降解过程的表观动力学参数.研究结果表明聚碳酸酯/ABS/蒙脱土纳米复合材料具有较高的热稳定性和阻燃性.两种材料的热氧化降解模型是一个两步分解过程.     

镁铝双氢氧化物对无卤阻燃EVA的协效阻燃效果研究

利用共沉淀法合成了镁铝双氢氧化物（MgAl-LDH）,采用熔融共混的方法,制备了含Mgal—LDH片层的无卤阻燃EVA纳米复合材料,通过多种表征手段分析研究了MgAl-LDH对无卤阻燃EVA（乙烯-醋酸乙烯酯共聚物）的协效阻燃效果。扫描电镜（SEM）和透射电镜（TEM）的结果表明LDH的片层能够促进阻燃剂在EVA基体中的分散;锥形量热仪（Conecalorimetry）燃烧测试表明协效阻燃EVA的热释放速率相对于纯阻燃EVA显著降低,其他主要燃烧参数也有同样的变化趋势,说明MgAl-LDH具有良好的协效阻燃作用。材料的燃烧残余物的形貌分析表明,LDH协效阻燃EVA在燃烧过程中能形成致密而连续的保护层,有效阻隔材料在燃烧过程中气体挥发物的扩散和与燃烧环境间能量的交换,提高燃烧残留量,降低材料的火灾危险性。     

基于石墨烯-氧化镍杂化物与二氧化钛纳米管协效阻燃环氧树脂的制备及研究

通过共沉淀法制备了石墨烯-氧化镍杂化材料,通过水热法制备了二氧化钛纳米管,然后利用溶液共混法制备了石墨烯-氧化镍/二氧化钛纳米管/环氧树脂纳米复合材料。利用X射线衍射仪(XRD)、拉曼光谱仪和透射电子显微镜(TEM)对纳米材料的结构和形貌进行表征;热重分析数据表明复合材料的热稳定性有所提高;锥形量热测试结果显示,将石墨烯-氧化镍杂化物与二氧化钛纳米管进行复配,加入环氧树脂中,可以有效降低材料的热释放速率峰值和总热释放。     

聚乙烯醇 /氧化石墨插层和层离纳米复合材料结构的观察

本文采用高分辨电镜首次观察到聚乙烯醇/氧化石墨插层和层离纳米复合材料结构并对其进行了表征,研究表明,高分辨电镜是一种研究氧化石墨插层和层离现象的很好的仪器。     

石墨烯环氧树脂复合材料的制备和阻燃性能的研究

合成并表征了石墨烯,然后通过溶剂法制备石墨烯/环氧树脂复合材料,研究了石墨烯对环氧树脂复合材料的热稳定性和燃烧性能的影响。热重分析数据显示,石墨烯可以显著提高环氧树脂的热稳定性。锥形量热仪测试结果表明,石墨烯降低了环氧复合材料热和烟气的释放。炭渣的扫描电镜(SEM)图揭示了石墨烯减少了环氧树脂炭层孔洞的生成,提高了炭层的致密度,从而增强了炭层的阻隔作用。     

玻璃纤维增强聚对苯二甲酸乙二醇酯/次磷酸铈复合材料的制备及其阻燃性能研究

首先合成并表征了一种新的阻燃剂-次磷酸铈（CHP）;然后采用熔融共混的方法制备了玻璃纤维（GF）增强聚对苯二甲酸乙二醇酯（PET）/CHP（PET/GF/CHP）复合材料;探讨了CHP对PET/GF复合材料热稳定性和燃烧性能的影响。材料的热稳定性是由热失重分析（TGA）进行表征的,燃烧性能是通过氧指数（LOI）、垂直燃烧（UL-94）以及锥形量热仪进行测试的,炭渣形貌由扫描电子显微镜（SEM）进行表征。结果表明：CHP的引入保持了PET/GF的热稳定性。含有15wt%CHP的PET/GF材料（PET/GF/CHP15）,其LOI为30%,且能达到UL-94V-0级别。此外,与PET/GF相比,PET/GF/CHP15热释放速率峰值和热释放总量分别下降了67%和27%。SEM分析表明CHP的加入使得材料在燃烧后有大量致密的炭渣覆盖在玻璃纤维的表面,这些炭渣不仅降低了玻璃纤维的导热性,而且切断了可燃物质的传送通道,从而提高了材料的阻燃性能。     

Effect of particle size distribution,drying and milling technique on explosibility behavior of olive pomace waste

The Mediterranean area is responsible for about 98% of the olive oil worldwide production, with 900 million olive trees occupying 10 million hectares. However, the processing of 100 kg of olives leads to the production of 40 kg of wastes, mainly constituted by olive pomace, which is potentially recoverable as energetic or material source. In general, in the past 20 years, the exploitation of olive pomace has increased, but along with it, the need for further information about its chemical-physical characterization and the related hazard in industry. Thus, a risk analysis assessment was conducted. When pelletized or in chunks, olive pomace does not pose any greater hazard than a pile of woody material, but when pulverized, it might become dangerous. Two parallel series of experiments were carried out at Dalhousie University (Lab 1) and at Polytechnic of Turin (Lab 2) using the same olive pomace sample, according to slightly different experimental procedures. Olive pomace dust explosibility and flammability parameters were measured: minimum ignition energy (MIE), minimum ignition temperature (MIT), maximum pressure rise rate ((dP/dt)_max and K_St), maximum pressure (P_max), and minimum explosible concentration (MEC). Moreover, the chemical and physical characterization of olive pomace was carried out: moisture content, particle size analysis, Scanning Electronic Microscope (SEM) investigation, thermo-gravimetric analysis (TGA), solid-state Nuclear Magnetic Resonance (NMR), mass spectrometry, calorific value, and bulk density estimation. Different thermal behaviors were observed according to the sieving/grinding pre-treatment. As concern flammability tests, samples seemed not to be sensitive to electric arc ignition (a value of MIE could not be measured), while coarser samples demonstrated higher ignition sensitivity to hot environment sources (MIT furnace) than finer ones. On the other hand, explosion violence parameters were enhanced by decreasing the particle size, while peak pressures were significantly influenced by the heat of combustion and the moisture content. Finally, a new test was developed to quantify the propensity of the raw material to produce fines by abrasion. It is defined “Abrasion by Rolling Test” (ART). The properties of the fines produced were measured as well.     

盐度胁迫对云纹石斑鱼鳃离子调节酶及渗透压的影响

为探讨云纹石斑鱼鳃离子调节酶活力及血清渗透压对盐度骤降的响应,设置4个盐度梯度(27、21、15和9)对云纹石斑鱼进行盐度骤降胁迫试验,在0、1 d、2 d、3 d和7 d时取样,测定其鳃中Na+/K+-ATP(NKA)酶、Ca~(2+)-ATP酶(Ca~(2+)-ATPase)、琥珀酸脱氢酶(SDH)、乳酸脱氢酶(LDH)活力及血清渗透压。结果表明,盐度21组与15组NKA及Ca~(2+)-ATPase活力在第1 d大幅上升,显著高于对照组(p0.05),随后下降趋于稳定,而盐度9组NKA及Ga2+-ATPase活力一直呈下降趋势;血清渗透压呈先下降后上升的变化趋势(p0.05);SDH活力变化与离子酶一致(p0.05);LDH活力变化与离子酶相反(p0.05)。研究表明,在盐度骤降的情况下,云纹石斑鱼鳃进行渗透压调节分为两个阶段,一是应激反应阶段,此时NKA及Ca~(2+)-ATPase迅速升高,血清渗透压降低;二是适应阶段,离子酶活力下降趋于稳定,血清渗透压升高恢复至正常水平,而且SDH与LDH酶活力也相应变化,为渗透压调节提供能量。     

Study of lignocellulosic biomass ignition properties estimation from thermogravimetric analysis

In the last decade, the use of renewable resources has increased significantly in order to reduce the energetic dependence on fossil fuels, as they have an important contribution to the global warning and greenhouse gasses effect. Because of that, research on biofuels has been increased in the last years as its characteristics of use match those of the conventional fuel's: solid biomass can be used instead of coals, and biodiesel could replace diesel. Research on solid biomass ignition properties has been considerably developed because of the amount of industrial accidents related to the treatment and use of solid biomass (self-ignition, dust explosions, etc.). On the other hand, thermogravimetric analysis (TGA) is becoming and important characterization technique as it can be used to determine a wide spectrum of properties, such as kinetics, composition, proximate analysis, etc. This research aims to combine thermal analysis and ignition properties, by using the TGA to obtain the elemental composition of lignocellulosic biomass and compare those results to Minimum Ignition Energy (MIE) values test output, so a relation between composition and MIE can be found.To achieve this aim, biomass samples from different origins have been used: oil palm wastes (empty fruit bunches, mesocarp fiber and palm kernel shell), agricultural wastes (straw chops) and forestry wastes (wood chips and wood powder). Also, raw materials and torrefied biomass were compared. The hemicellulose/cellulose ratio was calculated and compared to different flammability properties, finding out that the greater the ratio and the lower the onset temperature (temperature at which the pyrolysis reaction accelerates), the lower was the minimum ignition energy. From this basis it was possible to define “tendency areas” that grouped the samples whose MIE values were similar. Three tendency areas were found: high minimum ignition energy, medium minimum ignition energy, and low ignition energy.