插层改性水滑石对聚丙烯阻燃及力学性能的影响

通过阴离子交换的方法制备了对氨基苯磺酸(AB)插层水滑石(AB-LDHs),通过熔融共混的方法制备了阻燃性能和力学性能较好的聚丙烯(PP)复合材料。通过红外光谱(FTIR)和X射线衍射(XRD)对改性水滑石表征,表明对氨基苯磺酸根离子部分插层水滑石。极限氧指数(LOI),垂直燃烧(UL-94)和热失重(TGA)的测试结果表明,无论LDHs还是AB-LDHs,都能使复合材料的LOI提高,抗熔滴时间延长,热稳定性和成炭率也提升,且AB-LDHs的效果更好。少量LDHs或AB-LDHs提高了复合材料的冲击强度。     

改性镁铝水滑石对PVC力学性能的影响

以钛酸酯偶联剂为改性剂对镁铝水滑石进行表面改性,研究了改性时间、钛酸酯偶联剂用量等因素对吸油值的影响,钛酸酯偶联剂改性镁铝水滑石的最佳条件为:钛酸酯偶联剂用量(质量分数)为5%,改性时间为50 min。通过改性前后XRD结构参数与标准参数的对比进行改性评价,并对改性前后的镁铝水滑石添加至PVC中进行了力学性能测试。实验结果表明:镁铝水滑石能改善PVC的力学性能,改性后镁铝水滑石/PVC复合材料的力学性能比未改性的镁铝水滑石/PVC有较大改善。     

类水滑石及其复配阻燃剂阻燃聚丙烯应用研究

以聚丙烯(PP)复合阻燃材料样条的极限氧指数(LOI)为主要考察指标,考察了类水滑石(LDHs)及其与焦磷酸哌嗪(PAPP)、次磷酸铝(AHP)等在不同质量比下复配添加对PP复合材料阻燃性能的影响。实验结果表明:当复配阻燃剂的添加量为40%,LDHs∶PPAP∶AHP质量比为3∶1∶1时,PP复合材料的LOI值由17.6%提高到28.6%,UL-94测试达到V-0级。添加了LDHs、PPAP、AHP的PP复合阻燃材料样条的弯曲和拉伸强度较单独添加LDHs时有所提高,力学性能得到明显改善。通过SEM分析和TG、DTG分析,初步认为不同质量比LDHs/PPAP/AHP的阻燃作用可简要概括为"协效成炭阻燃作用机制"。LDHs/PPAP/AHP的协效添加,明显提高PP复合材料的残炭率,样条燃烧后生成较厚的膨胀残炭层,提高了PP复合材料的阻燃性能。     

PP/改性滑石粉复合材料性能研究

以钛酸酯偶联剂为改性剂对滑石粉进行表面改性,然后将其填充到聚丙烯(PP)中,制成PP/改性滑石粉复合材料。考察了滑石粉用量对PP/滑石粉复合材料阻燃性能和力学性能的影响,并对比了滑石粉改性前后复合材料力学性能及阻燃性能的差异。结果表明:添加滑石粉可提高PP复合材料的阻燃性能和耐热性能。另外,未改性滑石粉的添加降低了PP复合材料的力学性能,而适量改性滑石粉的添加(≤20 phr)则使复合材料的拉伸强度和冲击强度得到提升。     

插层改性水滑石及其对聚丙烯力学和阻燃性的影响

通过离子交换法制备了十二烷基磺酸钠、酒石酸氢钠、衣康酸改性的水滑石和十二烷基磺酸钠/衣康酸、十二烷基磺酸钠/酒石酸氢钠协同改性的水滑石（LDHs），通过熔融插层法制备得到了LDHs/PP复合材料。采用红外光谱（FTIR）、X射线衍射（XRD）、热重分析（TGA）对水滑石的结构和性能进行了分析表征，研究了LDHs/PP复合材料的力学性能和阻燃性。结果表明：上述几种单一和复合有机酸及盐改性剂都能不同程度地扩大水滑石的层间距；采用酸/盐协同改性的水滑石不仅有机基团含量较高，而且层间距大，显著提高PP的弯曲强度和阻燃性，表明酸和盐复合改性水滑石有显著协同作用及改性水滑石与PP基体相容性好。     

油酸钠改性锌镁铝水滑石的制备及对聚丙烯的增强作用

为改善水滑石(LDHs)的颗粒分散性和表面活性,提高LDHs填料与聚合物的界面相容性,采用快速成核/晶化法合成了锌镁铝水滑石(ZnMgAl-LDHs),并以油酸钠为表面改性剂,对ZnMgAl-LDHs进行了表面改性,通过粒度分析、X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、热重分析(TG)及扫描电镜(SEM)/透射电镜(TEM)对改性前后的ZnMgAl-LDHs进行了表征。将改性前后的ZnMgAl-LDHs分别添加到聚丙烯(PP)中,制得ZnMgAl-LDHs/PP复合材料,通过拉伸强度和弯曲强度测试考察改性前后ZnMgAl-LDHs的添加量对复合材料力学性能的影响。结果表明:所制备的ZnMgAl-LDHs的平均粒径为838.9 nm,当油酸钠的质量浓度为0.6 g/L时,平均粒径减小至647.2 nm。当ZnMgAl-LDHs添加量的质量分数为2%~8%时,改性前后的ZnMgAl-LDHs均对PP的力学性能有增强作用。改性ZnMgAl-LDHs具有更好的颗粒分散性,改性ZnMgAl-LDHs与PP相容性更好,对PP力学性能的增强作用优于未改性的ZnMgAl-LDHs。     

高岭土表面改性研究及应用

高岭土经过钛酸酯偶联剂(NDZ-105)表面改性后,与聚丙烯(PP)树脂熔融共混制备复合材料。考察了偶联剂用量、改性温度及改性时间对高岭土改性效果的影响;借助X射线衍射、红外光谱等测试手段,对改性前后的高岭土进行了表征分析。结果表明,最佳改性条件为:NDZ-105用量3%,改性温度80℃,改性时间1h。用改性高岭土制备的复合材料比用未改性高岭土制备的复合材料的拉伸强度、冲击强度、屈服强度、弹性模量及维卡软化点都明显提高。     

ZnAl-LDHs阻燃剂的改性及其在ABS中的应用

采用共沉淀法合成了ZnAl-LDHs,并以油酸钠为表面改性剂,对其进行湿法表面改性制备油酸钠改性的ZnAl-LDHs(O-ZnAl-LDHs)。通过X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、扫描电镜(FESEM)及热重分析(TG)对改性前后的ZnAl-LDHs进行了表征。将改性前后的ZnAl-LDHs分别添加至ABS中,制备ZnAl-LDHs/ABS复合材料,通过阻燃和力学性能测试考察了改性前后ZnAl-LDHs的添加量对复合材料性能的影响。结果表明:当添加量为10%~50%时,改性前后的ZnAl-LDHs均能使ABS复合材料极限氧指数(LOI)提高,当添加量为40%时,改性后的ZnAl-LDHs氧指数较未改性的ZnAl-LDHs有着明显提升且满足UL-94垂直燃烧测试的V-1级别要求;当改性后的ZnAl-LDHs添加量为50%时,LOI可达28.2%,且满足UL-94垂直燃烧测试的V-0级别要求;而力学性能相对于同等添加量下未改性的复合材料均有不同程度的提高。     

羟基锡酸锌/MPP-PER协同阻燃聚丙烯的性能研究

将三聚氰胺磷酸盐(MPP)、季戊四醇(PER)用于聚丙烯(PP)阻燃改性，研究了羟基锡酸锌(ZHS)对PP抑烟效果的影响。采用极限氧指数(LOI)、UL-94燃烧等级测试、烟密度、锥量测试分析了阻燃PP复合材料的阻燃性能。结果表明，MPP-PER复配能起到较好的阻燃协同作用，能有效提升聚丙烯复合材料的阻燃性能；ZHS的加入能显著降低聚丙烯复合材料的产烟量。当MPP-PER阻燃剂添加量为26%,ZHS的添加量为3%时，LOI达25.1%,UL-94通过V-2级(1.6 mm),燃烧最大比光密度(Ds_max)相比于纯PP降低了23.7%。     

偶联剂对线性低密度聚乙烯/水滑石体系力学和流变性能影响

采用钛酸酯偶联剂NDZ-201、硅烷偶联剂KH-570、硬脂酸和硬脂酸-稀土偶联剂,对水滑石(LDHs)进行表面改性处理,通过X射线衍射和红外光谱表征了改性前后LDHs的结构变化;并研究了不同种类偶联剂及其含量对LDHs填充LLDPE复合体系的力学性能和流变性能的影响.结果表明:4种偶联剂均可以实现LDHs表面改性,并且不会改变LDHs层状结构;改性后LLDPE/LDHs复合材料的断裂伸长率和流变性能得到提高;其中用4%硬脂酸改性LDHs时,LLDPE/LDHs复合材料的断裂伸长率为160%,平衡扭矩为8 N·m.     

Flammable,thermal, and mechanical properties of intumescent flame retardant PP/LDH nanocomposites with different divalent cations

The flammable, thermal, and mechanical properties of intumescent flame retardant (IFR) polypropylene/layered double hydroxide (PP/IFR/LDH) nanocomposites with the LDHs of different divalent cations and IFR system of ammonium polyphosphate/pentaerythritol (APP/PER) have been studied by X-ray diffraction (XRD), cone calorimeter test (CCT), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), limiting oxygen index (LOI), UL-94 test, and mechanical measurements. The XRD results show that the exfoliated PP/IFR/LDH nanocomposites possess the nanoscaled dispersion characteristic. The data from the CCT tests show the synergistic effect of LDHs with IFR can decrease considerably the HRR, MLR, and EHC values of the PP/IFR/LDH nanocomposites, in which the pk-HRR, pk-MLR, and pk-EHC values of the PP/IFR/ZnAl-LDH sample decrease to 318 kW/m², 0.081 g/m² s, 61.8 MJ/kg from the corresponding values 506 kW/m², 0.115 g/m² s, 71.8 MJ/kg of the PP/IFR sample. The LOI and UL-94 data further support the evidence that the flame retardant synergistic effects of LDHs with IFR increase the LOI values and UL-94 rating, especially for the LDHs with the transition ions (Zn, Cu) the LOI values can reach 33% and the UL-94 pass the V-0 rating. The TGA results demonstrate the LDHs can greatly improve the thermal stabilities of PP/IFR/LDH nanocomposites by increasing the thermo-oxidation decomposition temperature and charred residues. The morphological structures observed by SEM have demonstrated the LDHs can promote formation of compact charred layers. The data from the mechanical tests show the tensile strength and elongation at break of the PP/IFR/LDH samples are basically unchanged compared with the PP/IFR sample. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Synergistic flame retardant effects of Fe-OMMT with LDH in EVA/LDH composites

Abstract

The synergistic effects of Fe organic modified montmorillonite (Fe-OMMT) with layered double hydroxides (LDHs) in ethylene vinyl acetate copolymer/LDH (EVA/LDH) composites have been studied using thermal analysis [thermogravimetric analysis (TGA)], limiting oxygen index (LOI), UL-94 test and cone calorimeter test (CCT). The results showed that the addition of a given amount of Fe-OMMT apparently increased the LOI value and the rating in the UL-94 test. The results from the LOI and UL-94 tests show that Fe-OMMT can act as flame retardant synergistic agents in EVA/LDH composites. The CCT data indicated that the addition of Fe-OMMT in the EVA/LDH system can greatly reduce the heat release rate. The TGA data show that Fe-OMMT, as an excellent flame retardant synergist of LDH, cannot increase the thermal degradation temperature and the charred residues.     

Vinyl polysiloxane microencapsulated ammonium polyphosphate and its application in flame retardant polypropylene

Vinyl polysiloxane microencapsulated ammonium polyphosphate (MAPP) was prepared by a sol-gel method using vinyltrimethoxysilane as a precursor to improve its thermal stability and hydrophobicity. The MAPP was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and thermogravimetric analyzer (TGA). The results showed that ammonium polyphosphate (APP) was successfully coated with vinyl polysiloxane. MAPP and pentaerythritol (PER) were used together to improve the flame retardancy of polypropylene (PP). The flame retardant properties of PP composites were investigated by limiting oxygen index (LOI), UL-94 test, TGA and SEM. When the MAPP was added as a flame retardant, with PER as a char forming agent, the LOI of PP/MAPP/PER composites was 33.1%, and it reached the UL-94 V-0 level. The results also demonstrated that the flame retardant properties of PP/MAPP/PER composites were better than those of PP/APP/PER composites at the same loading. Moreover, the addition of flame retardant and carbon forming agent could promote the crystallization behavior of PP.     

有机化坡缕石黏土-膨胀型阻燃聚丙烯复合材料的制备及性能

制备了优异阻燃性能(LOI36%)兼具良好力学性能的膨胀型阻燃聚丙烯复合材料OPGS/PA-APP/PP。将有机化坡缕石黏土引入到哌嗪-多聚磷酸铵(PA-APP)膨胀型阻燃(IFR)聚丙烯(PP)复合材料中,通过极限氧指数(LOI)、垂直燃烧(UL-94)、热重分析法(TGA)、扫描电子显微镜(SEM)、通用电子万能试验机研究了有机化坡缕石黏土添加量对PA-APP阻燃聚丙烯复合材料阻燃性能和力学性能的影响。结果表明,添加质量分数为2%的有机化坡缕石黏土提高了该复合材料的阻燃性能和力学性能。此外,所制备样品经垂直燃烧测试可达到阻燃V-0级别。实验证明,有机化坡缕石黏土在膨胀型阻燃聚丙烯复合材料中具有明显的协效阻燃作用。     

聚苯基甲氧基硅氧烷改性环氧树脂的阻燃性能研究

采用氧指数(LOI),UL-94,热失重(TGA)等手段考察了聚苯基甲氧基硅氧烷(PPMS)改性对环氧树脂(E-20)固化体系阻燃性能的影响.相比未改性环氧体系,当m(E-20)∶m(PPMS)=73∶时,改性环氧体系的LOI由纯E-20环氧树脂的17.5%上升到21.5%;水平火蔓延速率由36.23 mm/min降低到26.60 mm/min;质量损失为5%时的热分解温度由134.7℃上升到163.0℃,750℃时残炭量由0.21%增加到25.79%.此外,还通过红外光谱对燃烧后的残炭结构进行了分析,探讨了相关阻燃机理.     

The flame retardant and thermal performances of polypropylene with a novel intumescent flame retardant

A novel mono-component intumescent flame retardant(m-IFR), called poly-(spirocyclic pentaerythritol bisphosphonate-1,3,5-triazine-O-bicyclic pentaerythritol phosphate) (PSTBP) was synthesized and characterized. PSTBP was used in polypropylene (PP) to obtain PP/PSTBP mixture whose flame retardancy, thermostability, and water resistance were studied by limiting oxygen index (LOI), vertical burning test (UL-94 V) and thermogravimetric analysis (TGA). In addition, flame-retardant mechanism of the PSTBP was investigated. The results showed that the residue of PSTBP reached 34.58% at 800°C and the volume of the PSTBP increased by dozens of times. When the content of PSTBP was 30.0 wt%, the PP/PSTBP mixture could achieve an LOI value of 32.5% and an UL-94 V-0 rating. Compared with PP/APP/PER system, PP/PSTBP mixture showed better water resistance. The TGA and Fourier transform infrared spectroscopy (FTIR) results showed that PSTBP could generate free radicals and capture the free radicals of the thermal decomposition of PP, and form a dense, strong, and thick intumescent char on the substrate, thus effectively retard the degradation and combustion of PP.     

Synthesis of a novel intumescent flame retardant and its flame retardancy in polypropylene

Microencapsulated ammonium polyphosphate (GMFAPP) is prepared by in situ polymerization method with a shell of poly(ethylene glycol) modified melamine-formaldehyde resin. Due to the presence of shell, GMFAPP shows less size, higher water resistance and flame retardancy in polypropylene (PP) compared with ammonium polyphosphate (APP). The flame retardant action of GMFAPP and APP in PP are studied using LOI, UL-94 and cone calorimeter, and their thermal stability is evaluated by thermogravimetric apparatus. The limiting oxygen index (LOI) value of the PP/GMFAPP at the same loading is higher than the value of PP/APP. UL-94 ratings of PP/GMFAPP can reach V-0 at 30 wt% loading. The water resistant properties of the PP composites are studied, and the results of the composites containing with APP and GMFAPP are compared. The cone results put forward that GMFAPP is an effective flame retardant in PP compared with APP. Moreover, the thermal oxidative behavior of GMFAPP is evaluated by dynamic FTIR to study its flame retardant mechanism in PP.     

Flammability,thermal stability,and mechanical properties of ethylene-propylene-diene monomer/polypropylene composites filled with intumescent flame retardant and inorganic synergists

Three kinds of inorganic particles, zinc borate (ZB), organic montmorillonite (OMMT), and expanded graphite (EG) as synergistic flame retardants, are incorporated into ethylene-propylene-diene monomer/polypropylene (EPDM/PP) composites filled with intumescent flame retardants (IFR). The effect of three synergistic flame retardants on the combustion, thermal stability, and mechanical properties of the EPDM/PP/IFR composites are investigated by limiting oxygen index (LOI), UL-94 test, cone calorimeter test (CCT), thermogravimetric analysis (TGA), scanning electron microscopy, mechanical property testing, and dynamic mechanical analysis (DMA). The results from LOI, UL-94, and CCT show that the synergistic effect of IFR with ZB and EG is better than IFR with OMMT in the flame retardant EPDM/PP/IFR composites. The TGA results indicate that the thermal stability and char residues of the composites is improved with the addition of inorganic particles, which is attributed to the formation of dense char layers to isolate heat flow. DMA results including storage modulus (G'), loss modulus (G"), and loss factor (tan δ) suggest that the composites with inorganic particles exhibit more rubber-filler interaction, which limits the movement of the rubber chains.     

苯基聚硅氧烷微胶囊化聚磷酸铵的制备及其在PP中阻燃性能研究

采用苯基三甲氧基硅烷为前驱体,通过溶胶凝胶法制备出苯基聚硅氧烷微胶囊化聚磷酸铵（MAPP）。将MAPP作为阻燃剂,季戊四醇（PER）作为成炭剂,制备阻燃聚丙烯（PP）。用傅里叶红外光谱、扫描电子显微镜、能谱仪及热重分析仪对MAPP进行表征。结果表明,聚磷酸铵（APP）被苯基聚硅氧烷成功包覆;较之APP,MAPP的热稳定性和疏水性显著提高;MAPP的阻燃性能优于APP,PP/MAPP/PER复合材料达到V-0级别;阻燃剂及成炭剂的加入对PP的结晶行为有促进作用。