表面改性对聚丙烯/纳米氢氧化镁复合材料性能的影响

研究了表面处理剂(钛酸酯和硅烷偶联剂)对聚丙烯/纳米氢氧化镁(MH)阻燃复合材料性能的影响。通过高压毛细管流变仪、LO I、力学测试、DSC和SEM对PP/纳米MH复合体系的结构与性能进行了研究。结果表明,所选偶联剂能有效地降低复合体系的表观黏度,改善体系的流动性。未改性的纳米MH对PP基体有异相成核作用;而表面改性剂能削弱填料对基体的异相成核作用。改性后的纳米MH粒子以独立形式均匀分散在基体中,PP与纳米MH界面的粘接力得到了加强,复合材料的拉伸性能和冲击强度有较大幅度的提高,阻燃性能也得到了改善。     

无卤阻燃剂的添加量对EVA发泡材料发泡性能的影响

针对EVA无卤阻燃发泡体系,研究了氢氧化镁(MH)、氢氧化铝(ATH)和红磷3种阻燃剂对EVA体系发泡性能的影响。结果表明:添加MH、ATH会使体系的粘度、发泡压力提高,交联度下降,过量的MH和ATH会导致发泡材料表面鼓泡,发泡倍率降低。添加红磷,体系的粘度、交联度下降,发泡压力、发泡倍率增大。为了保证EVA材料的顺利发泡,MH、ATH单独使用时,添加量分别不超过55%和50%(质量分数),阻燃剂复配使用时,添加量不能超过50%(质量分数)。添加MH、ATH和红磷会影响EVA材料的发泡性能。     

纳米SiO_2协效纳米Mg(OH)_2阻燃EVA的研究

以纳米二氧化硅(SiO_2)为协效剂,协效纳米氢氧化镁(MH)阻燃乙烯-醋酸乙烯酯(EVA),并制得纳米SiO_2/MH/EVA复合材料。采用傅里叶红外光谱仪(FT-IR)、热重分析仪(TG)、扫描电子显微镜(SEM)、氧指数和垂直燃烧测定法对材料的性能进行测试。结果表明:纳米SiO_2与纳米MH间有明显的协同作用,SiO_2含量为6%(wt,质量分数),MH为44%(wt,质量分数),制得的纳米SiO_2/MH/EVA复合材料的阻燃体系氧指数为30.8%,阻燃等级为V-0级,断裂伸长率达到726%,拉伸强度达到3.82MPa。SiO_2/MH在EVA中分散优于纳米MH,纳米SiO2可以有效改善复合材料的力学性能和阻燃性能。     

氢氧化镁的改性及其填充聚丙烯复合材料的燃烧性能和结晶行为的研究

研究了硅烷改性剂对氢氧化镁(MH)的表面改性和其填充聚丙烯(PP)复合材料的阻燃性能和结晶行为.用FTIR、XRD和SEM对改性前后MH的结构和形貌进行了分析.结果表明,硅烷处理剂包覆在MH粉体的表面,有效地降低MH粉体的表面能,提高了MH在干态下的分散性.DSC、POM和LOI对PP/MH复合材料的结晶行为和燃烧性能进行了研究.结果表明,未改性的MH对PP有异相成核作用,使结晶峰温度升高;而表面改性剂削弱了填料的异相成核作用.POM结果暗示了MH粒子在基体中的分散性对PP球晶的晶粒形貌和晶粒尺寸起着十分重要的作用.改性后的MH能进一步提高复合材料的LOI.     

改性水镁石对聚丙烯/三元乙丙橡胶复合材料性能的影响

水镁石粉体的主要成分为氢氧化镁,作为阻燃荆使用具有不含卤素、加工温度高、低成本等一系列优点,具有广阔的应用前景.以聚丙烯(PP)/三元乙丙橡胶(EPDM)为基体树脂,加入不同表面改性水镁石制备无卤阻燃PP/EPDM复合材料,探讨了不同表面改性水镁石对PP/EPDM/MH无卤阻燃复合材料阻燃性能和力学性能的影响.结果表明,改性后的MH-B提高了水镁石粉体在聚合物基体中的分散性,以及与聚合物基体之间的相容性,增强了材料的力学性能和阻燃性能,在添加量达到175phr时,氧指数可达到29.5%,同时拉伸强度达到12.5MPa,断裂伸长率保持在425%.     

高填充量耐油乙烯-醋酸乙烯酯共聚物电缆材料的制备及性能

应用聚硅氧烷低聚物(FPSO)对二氧化硅(SiO_2)、氢氧化铝(ATH)和氢氧化镁(MH)的混合物进行改性,并将改性后的无机混合物与乙烯-醋酸乙烯酯共聚物(EVA)进行熔融共混复合,制备出无机物填充量达50%的EVA电缆材料。采用扫描电镜(SEM)、差示扫描量热仪(DSC)、旋转流变仪、万能试验机和极限氧指数测试仪对EVA电缆材料的结构和性能进行表征与测试。SEM结果显示,FPSO的引入促进了高含量无机混合物在EVA基体中的分散,材料燃烧后的炭渣表面结构完整;DSC测试结果表明,FPSO含量较低时,EVA的结晶能力提高,有利于电缆材料力学性能的改善。流变测试结果揭示,FPSO的引入在削弱填料间相互作用的同时提高了无机粒子与基体间的界面黏结力,有利于提高材料的耐油及阻燃性能;当FPSO的质量分数为0.48%时,电缆材料具有较好的力学、耐油及阻燃性能。     

双交联体系互穿聚合物网络对石墨烯/乙烯-醋酸乙烯酯共聚物/高密度聚乙烯复合材料抗静电性能的影响

以高密度聚乙烯(HDPE)、乙烯-醋酸乙烯酯共聚物(EVA)为基体材料,石墨烯为导电填料,2,5-二甲基-2,5-双(叔丁基过氧基)己烷(DBPH)、三烯丙基异氰脲酸酯(TAIC)为交联剂,通过物理-化学方法在2种交联剂的协同作用下制备了具有互穿聚合物网络(IPN)结构的石墨烯/EVA/HDPE复合材料。实验结果表明,所用2种交联剂的协同作用能使复合材料的交联度达到54.3%。扫描电镜图中可以观察到EVA和HDPE形成的IPN结构可以促使石墨烯在复合材料基体中形成较完善的网络结构。实验结果还表明网络结构能在复合材料达到抗静电性能标准的情况下,很大程度上减少了石墨烯在EVA/HDPE基体中的添加量。当复合材料的交联度为40%~50%时,会出现类渗流阈现象,石墨烯的质量分数为2%时,复合材料的拉伸强度达到28.1 MPa,体积电阻率达到10~8Ω·cm。     

紫外光交联乙烯-醋酸乙烯共聚物/氢氧化镁无卤阻燃复合材料及其性能

研究了乙烯-醋酸乙烯共聚物(EVA)/氢氧化镁(MH)无卤阻燃复合材料在光引发剂下的紫外光交联及其相关性能。采用凝胶含量测定、热延伸试验、UL-94垂直燃烧试验、极限氧指数、扫描电镜、热重分析、拉伸测试等表征了复合材料的交联度、阻燃性能、热性能和力学性能。凝胶含量和热延伸测试结果证明紫外光可以对复合材料快速交联。光照交联后,材料的拉伸强度得到明显提高,断裂伸长率略有下降;极限氧指数、热重分析、扫描电镜测试表明光交联的复合材料试样比未交联的试样具有更好的阻燃性能和热稳定性。     

Mg(OH)2-Al(OH)3-微胶囊红磷/高抗冲聚苯乙烯无卤阻燃复合材料

以氢氧化镁(MH)、氢氧化铝(ATH) 和微胶囊红磷(MRP) 为无卤阻燃剂, 高抗冲聚苯乙烯(HIPS) 树脂为聚合物基体, 通过熔融共混法制备了一系列不同组成的MH-ATH-MRP/HIPS复合材料。采用水平燃烧、垂直燃烧、氧指数、锥形量热分析、高温热分解实验等方法研究了复合材料的阻燃性能。结果表明, 阻燃剂用量相同时, 在HIPS基体中同时引入MH和ATH得到的复合材料比单独加入MH或ATH得到的复合材料具有更好的阻燃性能。当MH-ATH/HIPS的质量比为70:30:100时, 复合材料的水平燃烧级别达到FH-1级, 氧指数为25.2%, 但垂直燃烧无级别。在上述体系中加入极少量的MRP(占复合材料的质量分数为2.9%)就可使复合材料的火灾性能指数(FPI) 提高85%, 燃烧过程中热量释放和质量损失更慢、成炭能力明显增强, 垂直燃烧级别达到FV-0级。当MH-ATH-MRP/HIPS的质量比为21:9:12:100时, 复合材料的各项阻燃性能达到最佳, 可以大幅度减少阻燃剂的用量。MH、ATH和MRP对HIPS具有非常显著的协同阻燃作用。同时加入MH和ATH时不仅可以在更宽的温度范围内抑制HIPS的升温和分解, 而且能够在更宽的温度范围内相继释放出水蒸气稀释氧气和可燃气体的浓度, 从而起到协同阻燃作用。加入MRP后复合材料的成炭能力大大增强, 进一步改善了凝聚相阻燃的效果, 因此阻燃性能显著提高。     

镁铝复配无卤阻燃剂对EVA/LDPE性能影响研究

以氢氧化镁(MH)和氢氧化铝(ATH)为无卤基材,结合硼酸锌、红磷和硅酮复配制备无卤阻燃剂。将阻燃剂进行改性后与EVA/LDPE共混制备新型无卤阻燃材料。通过正交试验法,研究不同配方无卤阻燃剂对材料的拉伸性能和阻燃性能的影响,进而获得最佳的复配阻燃剂配方。结果表明,在ATH和MH总量为60份的情况下,当MH∶ATH为5∶1,硼酸锌加入量20份,红磷加入量4份,硅酮用量为3份时,复配后无卤阻燃剂对EVA/LDPE的阻燃性能满足垂直燃烧等级UL-94V-0级,机械性能也较好。     

Improving flame retardant and mechanical properties of ethylene–vinyl acetate by cured compound silicone decorated magnesium hydroxide

Generally, the combustion of ethylene–vinyl acetate (EVA) can be effectively suppressed by the incorporation of 50 wt% magnesium hydroxide (MH), but with limited control on matrix dripping and serious deterioration on its mechanical property. In this work, a surface decorated MH by compound silicone resin (CCSi@MH) was prepared and integrated with red phosphorus (RP) introducing into EVA. The EVA/(5%RP?+?45%CCSi@MH) composite achieved V-0 rating in the UL 94 test with a limit oxygen index (LOI) of 31%. The dripping behavior was eliminated. Meanwhile, the mechanical properties were ameliorated by CCSi@MH, which was reflected in both static and dynamic mechanical test. The tensile strength and the elongation at break of EVA/(5%RP?+?45%CCSi@MH) composite were improved to 3.7 MPa and 52.3%, which were increased by 48% and 41%, respectively, compared with those of EVA/(5%RP?+?45%MH) composite. The prepared CCSi@MH provided an accessible method solving the dilemma brought by MH as flame retardant additives in EVA.

     

Cyclodextrin microencapsulated ammonium polyphosphate: Preparation and its performance on the thermal,flame retardancy and mechanical properties of ethylene vinyl acetate copolymer

Cyclodextrin microencapsulated ammonium polyphosphate (MCAPP) was prepared by the reaction between cyclodextrin (CD) and toluene-2,4-diisocyanate (TDI) with the goal of improving the water durability of APP and preparing a novel functional flame retardants. The Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectroscopy (XPS) results indicated MCAPP were successfully prepared, and the water contact angle (WCA) results indicated that cyclodextrin resulted in the transformation of hydrophilic to hydrophobic of the flame retardant surface. The MCAPP was then incorporated into the ethylene vinyl acetate copolymer (EVA) system and the effects of the MCAPP on the mechanical, combustion, thermal, interfacial adhesion and flame-retardant properties of EVA cable were investigated and compared by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), limiting oxygen index (LOI), mechanical test, cone calorimeter and UL-94 test. The characterization for the various properties of EVA composites demonstrated that cyclodextrin microencapsulation technology could enhance the interfacial adhesion, resulting in the improved mechanical, thermal stability, combustion properties and flame-retardant properties compared with those of EVA/APP/CD system. Furthermore, the water resistance experiments results demonstrate that EVA/MCAPP composites have good water durability due to the hydrophobic property of MCAPP. Above all, the microencapsulation of APP with cyclodextrin developed in this study may be a promising formulation for combining the acid source, the carbonization agent and the blowing agent in one flame retardant, and the MCAPP can solve the water resistance and the compatibility problem of the flame retardant during the industrial application.     

微胶囊化膨胀型阻燃剂与有机蒙脱土协效阻燃乙烯-醋酸乙烯共聚物性能

通过纳米复合的方式,将微胶囊化的膨胀型阻燃体系—聚磷酸铵(APP)-季戊四醇(PER)与有机改性的片层蒙脱土(OMMT)用于协效阻燃乙烯-醋酸乙烯共聚物(EVA)。采用XRD、TEM、TGA、极限氧指数(LOI)、垂直燃烧(UL-94)、锥形量热仪、烟密度和动态机械热分析对微胶囊化APP(MCAPP)-微胶囊化PER(MCPER)-OMMT/EVA复合材料的结构与性能进行研究。研究结果表明,OMMT被完全剥离开,并以层离或插层的状态分散在EVA中;MCAPP-MCPER与OMMT之间存在明显的协效阻燃作用,用3wt%OMMT代替MCAPP-MCPER后,MCAPP-MCPER-OMMT/EVA复合材料的LOI值从25.5vol%提高到29.5vol%,垂直燃烧结果由V-2上升到V-0级别,残炭量也由14.5wt%增大到15.9wt%,烟密度由154.7 g/s降低到97.5 g/s,材料的阻燃性能得到有效提高。此外,万能拉伸测试及动态机械热分析测试表明,通过纳米复合制备的阻燃MCAPP-MCPER-OMMT/EVA复合材料具有更好的力学和动态热机械性能。      

Preparation of silane precursor microencapsulated intumescent flame retardant and its enhancement on the properties of ethylene–vinyl acetate copolymer cable

Silane precursor microencapsulated intumescent flame retardant (IFR) was prepared by sol–gel process and then modified with vinyltrimethoxysilane (A-171) with the goal of that the vinyl group functionalized silica microcapsule could be introduced into EVA matrix through crosslinking, which will enhance the compatibility and dispersion between EVA matrix and microencapsulated IFR. The effects of silane precursor microencapsulation technology on the mechanical, electrical, thermal, interfacial adhesion and flame retardant properties of intumescent flame-retardant EVA cable were investigated by mechanical test, resistance meter, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), limiting oxygen index (LOI) and UL-94 test. The Fourier transform infrared (FTIR) results indicated silane precursor microencapsulated IFR were successfully prepared, and the water contact angle (WCA) results indicated that silane precursor results in the transformation of hydrophilic to hydrophobic of IFR surface. The characterization for the various properties of EVA composites demonstrated that silane precursor microencapsulation technology enhanced the interfacial adhesion, mechanical, electrical, thermal stability and flame retardancy of EVA/MCAPP/MCPER system. Furthermore, the water resistance test results demonstrate that EVA/MCAPP/MCPER composites have good water durability. This investigation provides a formulation for the industrial application as insulated materials of EVA cable with excellent properties.     

DOPOMPC-APP-MWCNTs协同阻燃环氧树脂的制备

将无卤膨胀阻燃剂六(4-DOPO羟甲基苯氧基)环三磷腈(DOPOMPC)、聚磷酸铵(APP)及多壁碳纳米管(MWCNTs)复配后加入环氧树脂(EP)中,制备出新型阻燃复合材料DOPOMPC-APP-MWCNTs/EP。通过极限氧指数(LOI)、水平垂直燃烧和锥形量热法研究其阻燃性能。研究结果表明:MWCNTs的加入增强了膨胀阻燃体系的阻燃性能和力学性能,并在一定程度上改善了体系燃烧时的浓烟现象。当阻燃体系总质量分数为20%,MWCNTs质量分数为2%时,材料性能最优,其LOI达到36.8%,热释放速率峰值、有效燃烧热平均值、比消光面积平均值和CO释放率平均值与未阻燃EP相比分别下降了83.5%、31.5%、47.6%、50.0%,与DOPOMPCAPP/EP相比下降了83.5%、77.7%、83.7%、68.9%。SEM分析表明:添加MWCNTs后,燃烧炭层呈现出大面积交联网络状结构。     

MCA-MMT的制备及其对玻璃纤维增强聚丙烯复合材料阻燃性能的影响

为了提高玻璃纤维(GF)增强聚丙烯(PP)复合材料(GF/PP)的阻燃性能,通过在蒙脱土(MMT)悬浮液中进行三聚氰胺氰尿酸盐(MCA)分子自组装制备了新型协效成炭剂MCA-MMT,并采用FTIR、XRD、SEM和TGA对MCA-MMT的结构及热性能进行了表征;将MCA-MMT、无卤膨胀型阻燃剂与GF/PP熔融共混制备了阻燃复合材料MCA-MMT/(GF/PP),通过极限氧指数(LOI)测试、垂直燃烧试验和锥形量热测试研究了MCAMMT对GF/PP的阻燃效果和阻燃机制,并测试了复合材料的力学性能。结果表明:MMT的加入会影响氰尿酸和三聚氰胺在MCA合成过程中的氢键作用,干扰和抑制大平面氢键网络的形成,减少MCA氢键复合体的分子体积,使颗粒变小。MCA-MMT/(GF/PP)的UL-94防火等级达到V-0级,LOI为31.3%。MCA-MMT的阻燃效率高于传统MCA的,可降低材料燃烧的热释放程度和总烟释放量,使复合材料的阻燃性能提高,其阻燃机制为片层结构的MMT可提高MCA的成炭量,使MCA-MMT/(GF/PP)燃烧后能形成致密的残留炭层。MCA-MMT/(GF/PP)的拉伸、冲击强度与MCA/(GF/PP)的相比并未下降。     

Effect of cellulose acetate butyrate microencapsulated ammonium polyphosphate on the flame retardancy, mechanical, electrical, and thermal properties of intumescent flame-retardant ethylene-vinyl acetate copolymer/microencapsulated ammonium polyphosphate/polyamide-6 blends

Ammonium polyphosphate (APP), a widely used intumescent flame retardant, has been microencapsulated by cellulose acetate butyrate with the aim of enhancing the water resistance of APP and the compatibility between the ethylene-vinyl acetate copolymer (EVA) matrix and APP. The structure of microencapsulated ammonium polyphosphate (MCAPP) was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and water contact angle (WCA). The flame retadancy and thermal stability were investigated by a limiting oxygen index (LOI) test, UL-94 test, cone calorimeter, and thermogravimetric analysis (TGA). The WCA results indicated that MCAPP has excellent water resistance and hydrophobicity. The results demonstrated that MCAPP enhanced interfacial adhesion, mechanical, electrical, and thermal stability of the EVA/MCAPP/polyamide-6 (PA-6) system. The microencapsulation not only imparted EVA/MCAPP/PA-6 with a higher LOI value and UL-94 rating but also could significantly improve the fire safety. Furthermore, the microencapsulated EVA/MCAPP/PA-6 composites can still pass the UL-94 V-0 rating after treatment with water for 3 days at 70 °C, indicating excellent water resistance. This investigation provides a promising formulation for the intumescent flame retardant EVA with excellent properties.     

干法表面改性对无机复合阻燃剂填充EVA材料的影响

研究水镁石颗粒表面包覆水合氧化锌型无机复合阻燃剂的干法表面改性及其在乙烯-醋酸乙烯共聚物(EVA)中的应用性能,并对改性和阻燃机理进行初步分析。结果表明,经改性的阻燃剂填充的EVA材料的阻燃性能和力学性能均得到提高,特别是力学性能有较大幅度提高,材料的氧指数为38.0%,拉伸强度为12.2 MPa,断裂伸长率为360%。红外光谱分析表明,表面改性剂通过物理缠绕和化学键合的方式附着在氧化锌包覆水镁石颗粒的表面,改变了氧化锌包覆水镁石颗粒的表面性质,提高了与有机聚合物的相容性。阻燃剂的阻燃范围在300~500℃,EVA起到了非常有效的阻燃作用。     

微胶囊Mg (OH)2的合成及其对乙烯-乙酸乙烯酯共聚物的阻燃作用

用原位聚合方法合成了以微米Mg（OH）₂粒子为芯材、交联聚脲为壁材的微胶囊Mg（OH）₂（M-Mg（OH）₂）阻燃剂,并把M-Mg（OH）₂加入到乙烯-乙酸乙烯酯共聚物（EVA）中,研究了M-Mg（OH）₂对EVA的阻燃作用。采用FTIR、SEM、热分析和酸滴定方法研究了M-Mg（OH）₂的性质,用极限氧指数（LOI）和垂直燃烧方法（UL-94）研究了M-Mg（OH）₂/EVA复合材料的阻燃性能以及酸腐蚀对M-Mg（OH）₂/EVA复合材料阻燃性能的影响。结果表明,采用原位聚合方法能够成功地在Mg（OH）₂粒子表面包覆交联聚脲壁材,得到M-Mg（OH）₂。与纯Mg（OH）₂相比,M-Mg（OH）₂的颗粒尺寸增大,热稳定性增加,在水中溶解度显著降低,在EVA基体中分散更加均匀。阻燃剂用量相同时,M-Mg（OH）₂/EVA复合材料的LOI总是比Mg（OH）₂/EVA复合材料的数值稍大。阻燃剂与EVA质量比小于135∶100时,两种复合材料的垂直燃烧级别均为V-2级,阻燃剂与EVA质量比在135∶100~150∶100之间时,前者的燃烧级别为V-0级,而后者只能达到V-2级,阻燃剂与EVA质量比超过150∶100时,两种复合材料都能达到V-0级。M-Mg（OH）₂/EVA复合材料的耐酸性比Mg（OH）₂/EVA大幅度提高,可以在酸性环境中使用。