包覆红磷在UPR包覆层耐烧蚀改性中的应用

为改善不饱和聚酯树脂(UPR)包覆层的耐烧蚀性能,在包覆层配方中引入有效阻燃剂包覆红磷.采用氧-乙炔烧蚀装置分别考察了包覆红磷与纳米Mg(OH)2、微米Mg(OH)2、Al(OH)3,三聚氰胺和硼酸锌复配填充UPR包覆材料的烧蚀性能.结果表明,包覆红磷与纳米Mg(OH)2复配时对UPR包覆层表现出较佳的耐烧蚀性能;当包覆红磷,纳米Mg(OH)2和UPR的质量比为30:20:100时,材料的线烧蚀率降至0.285mm/s,降低幅度为56%.用扫描电镜、热重分析仪对包覆红磷/纳米Mg(OH)2/UPR体系的耐烧蚀机理进行了分析.     

层状硅酸盐/橡胶纳米复合材料(二)凝聚共沉法制备的蒙脱土/天然橡胶纳米复合材料及其性能研究

以新鲜胶乳为主体材料,有机改性蒙脱土为填料,用凝聚共沉法制备了蒙脱土/天然橡胶复合材料,研究了复合材料的物理性能、动态力学性能及其热稳定性.结果表明,在天然橡胶中加入少量(3%～5%)的纳米蒙脱土,可以使橡胶的定伸应力、拉伸强度等性能大幅度提高,动态力学性能和耐热稳定性得到明显改善.     

蒙脱土的有机改性研究进展

蒙脱土由于具有独特的层状一维纳米结构特性,从而赋予了聚合物/蒙脱土纳米复合材料优良的性能,在基础研究和实际应用中都引起人们普遍的关注。本文针对钠基蒙脱土的有机改性,按不同的有机改性剂进行分类概述,综述了近年来国内外有机改性方面的研究进展 。同时介绍了有机改性蒙脱土/聚合物纳米复合材料的独特性能;最后,对蒙脱土的有机改性剂发展方向进行了展望：研制适合不同类型的聚合物/蒙脱土纳米复合材料的有机改性剂,提高纳米复合材料的力学性能、热力学性能及其它的特殊性能等,拓宽蒙脱土的应用领域。     

聚丙烯/有机蒙脱土/滑石粉纳米复合材料的制备与性能研究

采用双螺杆挤出机直接熔混的工艺,以聚丙烯(PP)为基体树脂,以滑石粉(Talc)和经有机改性的蒙脱土(OMMT)为填料,以马来酸酐接枝聚丙烯(MAH-g-PP)为相容剂,分别制备了PP/OMMT和PP/OMMT/Talc纳米复合材料。结果表明,所得PP/OMMT复合材料为蒙脱土剥离或部分剥离的纳米复合材料;PP/OMMT/Talc复合材料的性能优于两种填料分别填充改性的PP材料,且分散及改性效果基本没有互相影响;与传统PP/Talc复合材料相比,制备的PP/OMMT/Talc纳米复合材料在各性能相近或更好的前提下,密度可以减少7%～10%。     

蒙脱土对阻燃热塑性聚氨酯弹性体的增效作用

将有机改性蒙脱土(OMMT)与三聚氰胺聚磷酸盐(MPP)制得复配阻燃体系,并将其应用于热塑性聚氨酯弹性体(TPU)中以提高其阻燃性能。结果表明,当MPP/OMMT的质量比为23∶2时,体系的阻燃效果最好。与此同时,OMMT还可有效地提高TPU复合材料在高温段的热稳定性,稳定炭层,减少烟释放,增加最终残炭量,使TPU复合材料达到阻燃抑烟的效果。     

凝聚共沉法制备的蒙脱土／天然橡胶纳米复合材料及其性能研究

以新鲜胶乳为主体材料,有机改性蒙脱土为填料,用凝聚共沉法制备了蒙脱土／天然橡胶复合材料,研究了复合材料的物理性能、动态力学性能及其热稳定性。结果表明,在天然橡胶中加入少量（3％-5％）的纳米蒙脱土,可以使橡胶的定伸应力、拉伸强度等性能大幅度提高,动态力学性能和耐热稳定性得到明显改善。     

纳米膨润土(蒙脱土)在橡胶中的应用

蒙脱土( Montmorillonite)是属于蒙脱土族的矿物,是典型的层状硅酸盐矿物之一。通过衍射仪慢速扫描的试验结果表明,蒙脱土的粒度已接近纳米级,是天然纳米材料。纳米级有机膨润土在橡胶中主要用于橡胶制品的纳米改性,改善其气密性、定伸引力、耐磨性、防腐性、耐天候性、耐化学药品性。通过加入少量(如3 %～5% )的纳米蒙脱土,可以使橡胶的强度、伸长率等性能大幅度提高,有的性能可提高数倍,可替代目前的白炭黑,甚至彻底取代传统的炭黑及其它填料,大大减少或根除污染,将是二十一世纪橡胶工业的一场革命。聚氨酯弹性体/蒙脱土纳米复合材料、三…     

有机改性蒙脱土改性聚乳酸研究进展

聚乳酸是一种生物可降解高分子材料,具有较高的拉伸强度和良好的加工性能,但韧性较差。蒙脱土是一种层状硅酸盐纳米填料,具有高比表面积、低有效填充量、来源广泛和价格低廉等优点。采用有机改性蒙脱土纳米填料来改性聚乳酸,是一种提高聚乳酸性能的有效方法。综述了有机改性蒙脱土改性聚乳酸的4种方法,即直接共混改性聚乳酸、改性聚乳酸/韧性塑料共混物、改性聚乳酸/弹性体共混物、其他填料协同改性聚乳酸,介绍了其研究进展和存在的问题,并展望其前景。     

纳米蒙脱土在工程塑料PC中的应用及改性的PC工程塑料

采用固相插层法制备性能稳定的纳米蒙脱土母料;应用蒙脱土母料改性PC工程塑料,制备PC/蒙脱土纳米复合材料,改善了PC材料的加工性、耐应力开裂性能,同时提高PC材料的力学性能.     

多级拉伸挤出制备PP/OMMT纳米复合材料的性能研究

采用自行设计的多级拉伸设备制备了聚丙烯/有机改性蒙脱土纳米复合材料,并对复合材料的热稳定性,阻隔性能和流变学性能进行了研究。实验结果表明:多级拉伸挤出技术不仅能有效的使填料分散,并且能使有机改性的蒙脱土在基体中沿流动方向取向,从而在一定程度上提高复合材料的性能。     

聚磷酸铵阻燃体系对HIPS/OMMT阻燃研究

将钠基蒙脱土(Na~ -MMT)有机化改性,制成有机蒙脱土(OMMT),采用熔融插层法分别制备HIPS/OMMT复合材料和聚磷酸铵(APP)体系阻燃的HIPS/OMMT复合材料。结果表明,HIPS/OMMT复合材料具有一定的阻燃性能,但阻燃性能的提高比较有限;与仅添加OMMT时相比,APP体系阻燃的HIPS/OMMT复合材料的阻燃性和抑烟性均得到进一步提高,以APP、季戊四醇(PER)和硼酸锌(ZB)为膨胀型阻燃剂对HIPS/OMMT复合材料阻燃性和抑烟性的提高更为显著。力学性能测试结果表明,APP体系的加入对复合材料的拉伸强度和冲击强度都有负面影响。     

滑石粉及蒙脱土对PE80树脂的复合研究

研究了经表面处理的滑石粉和改性蒙脱土与PE80混合后材料力学性能的变化。结果表明:随着滑石粉用量的增加,其复合物弯曲模量显著提高,断裂伸长率缓慢下降;而少量的有机蒙脱土与PE80插层复合时,即可获得高强度和高韧性的复合材料。将滑石粉与蒙脱土共复合添加时,可以发挥蒙脱土片层剥离增强作用,从而以较少的添加量得到综合力学性能良好的复合材料。用XRD、SEM、TEM等对复合材料进行了结构表征。     

ATPU和蒙脱土复合增强不饱和聚酯的研究

用插层聚合法制备了不饱和聚酯（UPR）／丙烯酸酯封端聚氨酯（ATPU）／改性蒙脱土（OMMT）复合材料，探讨了ATPU和OMMT对复合材料的性能和形态的影响。结果表明，随着ATPU用量的增加，复合材料的冲击强度迅速提高，但复合材料的拉伸强度、弯曲强度、巴氏硬度和热变形温度降低；当OMMT少于质量分数3％时，UPR的冲击强度、拉伸强度和弯曲强度随OMMT用量的增大而提高，超过质量分数3％时，复合材料的冲击强度、拉伸强度和弯曲强度都下降。当OMMT和ATPU的用量分别为质量分数3％和15％时，拉伸强度提高约50％，而冲击强度和弯曲强度分别提高约8．6％和10．3％，热变形温度提高了12．5℃，收缩率降低了78％。     

碳/碳复合材料SiC–HfSi_2–TaSi_2抗烧蚀复合涂层

采用包埋技术在碳纤维增强碳(carbon fiber reinforced carbon,C/C)复合材料表面制备了碳化硅-硅化铪-硅化钽(SiC-HfSi2-TaSi2)抗烧蚀复合涂层.采用氧已炔火焰烧蚀试验评价了. C/C复合材料样品的抗烧蚀性能.通过X射线衍射分析、扫描电镜观察及能谱分析研究了SiC-HfSi-TaSi2作为 C/C复合材料抗烧蚀涂层的表面和断面相组成、元素分布及形貌.结果表明:由于烧蚀过程中生成的Hf02,Ta205具有高温稳定性,使得该涂层表现 出良好的抗烧蚀性能,在3 000℃下烧蚀20s后,线烧蚀率为0.009 mm/s,质量烧蚀率为0.003 85 g/s.     

MCA/APP协同作用对E/VAC燃烧性能与成炭机制的影响

通过筛选复配,组成了以三聚氰胺氰尿酸盐(MCA)为气源、聚磷酸铵(APP)为酸源的化学膨胀复配阻燃体系,用于对(乙烯/乙酸乙烯酯)共聚物(E/VAC)进行阻燃改性。通过极限氧指数(LOI)测试、垂直燃烧实验研究了MCA/APP协同阻燃作用对E/VAC燃烧性能的影响;并运用光学显微镜(OL)、扫描电子显微镜(SEM)和傅立叶变换红外光谱(FTIR)等分析手段对阻燃E/VAC体系燃烧后的结构进行了分析。结果表明,随着APP在MCA/APP体系中比例的增加,阻燃E/VAC的LOI由25.2%提高到28.3%;当MCA/APP配比为1.8∶1时,阻燃E/VAC的燃烧等级可以达到FV-0级;燃烧试样膨胀层的OL分析表明,随着MCA在MCA/APP体系中比例的增加,其膨胀层横截面处的孔洞增多、孔径变大,证明燃烧时形成了良好的膨胀和隔热层;燃烧试样炭层的OL和SEM分析表明,随着APP在MCA/APP体系中比例的增加,燃烧试样形成了具有良好阻燃效果的多孔泡沫状炭层;FTIR分析表明,阻燃E/VAC试样燃烧时发生脱水炭化现象。     

Construction of sandwich-structured C/C-SiC and C/C-SiC-ZrC composites with good mechanical and anti-ablation properties

Four kinds of sandwich-structured C/C-SiC and C/C-SiC-ZrC composites with or without a SiC interphase deposited by isothermal chemical vapor infiltration (ICVI), were designed and fabricated by a joint process of electromagnetic coupling chemical vapor infiltration (ECVI) and precursor infiltration and pyrolysis (PIP). The fabricated composites are macroscopically nonhomogeneous materials with low density, high strength and low ablation rate. The interphase and matrix constituents had remarkable effects on the mechanical and ablation properties of these composites. The C/C-SiC composites with an ICVI-SiC interphase exhibited the highest flexural strength of 306.5 MPa. While the C/C-SiC-ZrC composites with the interphase showed the best anti-ablation performance with low linear and mass ablation rates of 0.37 μm/s and 0.04 mg/cm²·s, respectively, after the ablation for 500 s under an oxyacetylene flame test at around 2000 °C.     

Experimental investigation of flame retardancy and mechanical properties of APP/EG/TPU multilayer composites prepared by microlayer coextrusion technology

In this paper, ammonium polyphosphate(APP)/expandable graphite(EG)/thermoplastic polyurethane (TPU) composites were prepared by microlayer coextrusion technology, APP and EG fillers had good synergistic flame retardancy and excellent dispersion in TPU matrix, which greatly improved the flame retardancy and mechanical properties of multilayer composites. The dispersion of APP and EG in TPU was characterized by using SEM, the flame retardancy of composites was characterized by using UL94 and LOI, the thermal stability of composites was characterized by using TGA and DTG, and tensile test was used to characterized the mechanical properties of composites. SEM showed that the microlayer coextrusion technology significantly improved the dispersion of APP and EG in TPU. As showed by the experimental results, the vertical combustion level of ordinary blended composites reached V-2 after adding only one kind of filler either APP or EG, and the vertical combustion level of ordinary blended composites reached V-0 with APP and EG applied together, while the vertical combustion level of microlayer coextruded composites all reached V-0 when the total addition of APP and EG was 15%. In particular, the LOI value of microlayer coextruded composites was 30.9%, while the LOI value of ordinary blended composites only was 27.9% when APP: EG = 1: 1. At this time, the flame retardancy level of APP/EG/TPU composites was the best. In addition, the thermal stability and mechanical properties of microlayer coextruded composites were far superior to ordinary blended composites. In conclusion, the synergistic flame retardancy of APP and EG fillers and the dispersion of APP and EG fillers in TPU matrix played a significant role in enhancing flame retardancy and mechanical properties.     

Flame retardancy of unsaturated polyester composites with modified ammonium polyphosphate,montmorillonite, and zinc borate

Ammonium polyphosphate (APP) was modified using a new method, where the resulting modified APP (MAPP) was obtained by mixing APP with unsaturated polyester resin (UPR). MAPP was more effective in improving the flame retardancy of UPR than APP which was due to the improved dispersion of MAPP in UPR composite. Then, the UPR composites were prepared based on dimethyl methylphosphonate, MAPP, montmorillonite, and zinc borate. Finally, the flame-retardant and mechanical properties of the UPR composites were analyzed using the limited oxygen index (LOI), thermogravimetric analysis, UL-94 vertical burning test, scanning electron microscopy, cone calorimetry, mechanical tests, and viscosity measurements. The LOI and UL-94 tests showed that the flame-retardant properties clearly improved with the addition of fillers in the UPR composites compared to pristine UPR. The synergistic effect of Si- and P-containing flame retardants in this composite resulted in the LOI value increasing from 18.9 to 31.3% and achieved the UL-94 V-0 rating. Moreover, the heat release rate was lower than the pristine UPR. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47180.     

Synergistic effect of organo‐montmorillonite on intumescent flame retardant ethylene‐octene copolymer

Nanocomposite of thermoplastic elastomer ethylene‐octene copolymer/maleated ethylene‐octene (POE/POE‐g‐MAH) with organo‐montmorillonite (OMMT, 11 wt %) as masterbatch have been obtained by melt blending and it has been characterized by transmission electron microscopy (TEM). Flame retardant POE/POE‐g‐MAH/OMMT/ammonium polyphosphate‐pentaerythritol (APP‐PER) (an intumescent flame retardant with 75 wt % ammonium polyphosphate and 25 wt % pentaerythritol) composites were prepared by using melting processing to study their structures, flame‐retardancy, thermal, and mechanical properties. TEM showed exfoliated structures throughout POE/POE‐g‐MAH/OMMT masterbatch and POE/POE‐g‐MAH/OMMT/APP‐PER nanocomposites. Synergistic effect was observed between OMMT and APP‐PER resulting in significant improvements on thermal stability, flame‐retardancy and mechanical properties in the POE/POE‐g‐MAH/OMMT/APP‐PER nanocomposites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013