纳米ZnO/PP及ZnO/CaCO_3/PP复合材料的性能研究

纳米氧化锌(ZnO)与聚丙烯(PP)通过熔融共挤制得了ZnO/PP纳米复合材料.研究了ZnO/PP纳米复合材料的力学、流变学性能与纳米ZnO添加量之间的关系;同时制备了ZnO/CaCO3/PP三元纳米复合材料并对其进行了机械性能和制备成本分析.结果表明,ZnO/PP纳米复合材料的熔体质量流动速率较纯PP有较大程度的提高;纳米CaCO3的加入不但可以降低生产成本,而且可以显著改善体系的冲击韧性;材料的拉伸破坏属于韧性断裂过程.     

硬脂酸对纳米ZnO填充聚丙烯流变和结晶行为的影响

为了给纳米ZnO/聚丙烯(PP)复合材料的加工及性能优化提供理论依据,采用熔融共混的方式制备纳米ZnO/PP复合材料,通过扫描电子显微镜(SEM)、旋转流变仪、差示扫描量热仪(DSC)以及X射线衍射仪(XRD)对纳米ZnO/PP复合材料的结构与性能进行表征,以研究硬脂酸加入前后对复合材料的微观结构、流变性能及结晶行为的影响。结果表明,当纳米ZnO质量分数低于5%时,粒子分散良好,复合材料熔体的复数黏度随纳米ZnO质量分数的增大而减小,但是当纳米ZnO质量分数高于10%后,纳米粒子发生团聚,体系黏度上升。硬脂酸的加入增强了ZnO纳米粒子与PP基体的界面作用,也改善了ZnO纳米粒子的分散性。纳米ZnO质量分数小于5%时,对PP结晶没有明显影响,但是当纳米粒子团聚后对PP起异相成核作用。硬脂酸的加入可以有效抑制复合材料中的PP在升温过程中β晶向α晶的转变。ZnO纳米粒子的团聚对β晶的形成起抑制作用。     

PP/LGF复合材料的膨胀性阻燃与协效阻燃性能

采用膨胀型阻燃剂(IFR)及协效剂海泡石(SP)对长玻璃纤维增强聚丙烯(PP/LGF)复合材料进行阻燃,通过双螺杆挤出机制备了PP/LGF母粒,IFR母粒和SP母粒,然后将这3种母粒通过注塑机制备了PP/LGF/IFR/SP复合材料,通过极限氧指数(LOI)、垂直燃烧测试、锥形量热仪、热重分析、扫描电子显微镜、力学性能测试等表征PP/LGF各阻燃复合体系的性能。结果表明,当IFR质量分数为22%时,PP/LGF/IFR阻燃复合材料的LOI为28.8%,且垂直燃烧等级达到V–0级;锥形量热仪测试结果表明加入IFR及SP后阻燃复合体系的第一热释放速率峰值降低,而第二热释放速率峰消失;SP质量分数为1%,IFR质量分数为21%的PP/LGF/IFR/SP阻燃复合材料LOI为29.6%,垂直燃烧等级达到V–0级,热释放速率峰值和总热释放量得到有效降低,热稳定性最好,且燃烧时产生致密的炭层覆盖于玻璃纤维表面,同时加入1%SP后复合材料的力学性能下降幅度相对较小。     

棉纤维/氢氧化铝/环氧树脂复合材料制备及性能分析

以硅烷偶联剂氨丙基三乙氧基硅烷(KH550)为改性剂,将改性处理后的棉纤维(CF)与氢氧化铝(ATH)和环氧树脂(EP)共混,制备得到棉纤维/氢氧化铝/环氧树脂(CF/ATH/EP)复合材料。通过测试复合材料的力学性能、剪切强度、极限氧指数(LOI)、热释放速率、抗紫外性能及拉伸断裂面微观形貌,分析了CF/ATH的用量比对复合材料综合性能的影响。结果表明:当CF/ATH的用量比为20/30时,复合材料具有较为优异的性能,LOI达到30.6%,垂直燃烧等级为V-0级,热释放速率为234.35 kW/m~2,剪切强度最佳为19.4 MPa,复合材料具有优良的抗紫外性能,可以制备得到综合性能较佳的高模量阻燃抗紫外纺织服装材料。     

纳米CaCO3对PP/BF复合材料性能影响

以甘蔗渣纤维(BF)、聚丙烯(PP)为原料,添加纳米碳酸钙(CaCO3)挤出制备PP/BF/CaCO3复合材料.通过复合材料的力学性能测试及傅里叶变换红外光谱(FTIR)、热重(TG)分析、扫描电子显微镜(SEM)等探究纳米CaCO3含量对PP/BF/CaCO3复合材料的影响.结果表明,添加质量分数9％的纳米CaCO3...     

纳米ZnO/PP及ZnO/CaCO_3/PP复合材料的性能研究

用纳米氧化锌(ZnO)与聚丙烯(PP)通过熔融共挤制得了ZnO/PP纳米复合材料,研究了ZnO/PP纳米复合材料的力学、流变学性能与纳米ZnO添加量之间的关系;同时制备了ZnO/CaCO3/PP三元纳米复合材料并对其进行了机械性能和制备成本分析。结果表明:ZnO/PP纳米复合材料的力学性能随纳米ZnO添加量的增加表现出冲击韧性先升后降,拉伸强度变化不敏感的特点;纳米CaCO3的加入不但可以降低生产成本,而且可以显著改善体系的冲击韧性;材料的拉伸破坏属于韧性断裂过程。     

MoO_3在聚烯烃/MH-EG阻燃体系中的协效作用研究

以氢氧化镁(MH)和可膨胀石墨(EG)为阻燃剂制备了阻燃聚烯烃(PO)材料,研究了三氧化钼(MoO_3)在该体系中的阻燃协效作用。结果表明:当MH添加量为40%时,阻燃PO的极限氧指数(LOI)仅为24.4%,继续加入6phr EG后,阻燃PO的LOI提高至28.2%,但不能提升材料的垂直燃烧等级。在PO/MH-EG体系中加入1 phr MoO_3后,材料的LOI达到29.5%,并通过UL 94V-0测试。此外,热重分析(TGA)和锥形量热(Cone)数据显示,MoO_3的加入可以促使材料提前交联成炭,提高材料的残炭率。与PO/MH-EG体系相比,PO/MH-EG-MoO_3阻燃材料的热释放速率峰值(PHRR)和烟释放速率峰值(PSPR)分别降低了40.98%和56.76%。     

PP/ZnAl-LDH纳米阻燃材料的燃烧特性

以自制的锌铝型纳米层状双氢氧化物(Zn Al-LDH)(n(Zn2+):n(Al3+)=3∶1)与聚丙烯(PP)熔融共混制备了PP/Zn Al-LDH纳米阻燃材料,利用锥形量热仪及场发射扫描电镜,表征并分析了PP/Zn Al-LDH纳米阻燃材料的燃烧特性。结果表明,与纯样PP相比,PP/Zn Al-LDH纳米复合材料的热释放速率(HRR)和CO释放率均大幅降低,不同比例PP/Zn Al-LDH的纳米复合材料燃烧完成后,得到不同比率的残渣。研究结果表明:Zn Al-LDH的加入降低了材料的热危害和毒气危害,并通过对材料的催化成炭作用发挥了较好的阻燃作用,降低了材料的火灾危险性。且当Zn AlLDH的添加用量为2. 1%～3. 5%时,PP/Zn Al-LDH纳米复合材料达到了最佳的阻燃效果。     

硅胶与膨胀型阻燃剂复配阻燃LGF/PP复合材料的性能研究

研究硅胶(SG)作为协效剂与IFR协同阻燃LGF/PP复合材料的性能。通过极限氧指数(LOI)、垂直燃烧(UL-94)、锥形量热仪(CONE)、热重分析法(TG)、扫描电子显微镜(SEM)、力学性能等测试表征LGF/PP/IFR/SG阻燃复合体系的性能。结果表明:当硅胶用量为2%时,阻燃复合材料的LOI为29.4%,且燃烧等级达到V-0级;CONE测试结果表明LGF/PP/IFR/SG阻燃复合材料的第一热释放速率峰值降低,而第二热释放速率峰消失;LGF/PP/IFR/SG阻燃复合材料具有较好的热稳定性,且产生致密均匀的炭层;并研究硅胶用量对复合材料力学性能的影响。     

磷-氮-锡膨胀阻燃剂阻燃聚丙烯的性能研究

在三嗪成炭剂和聚磷酸铵复配基础上,添加少量羟基锡酸锌(ZHS)作为协效剂,复配成磷-氮-锡(P-N-Sn)膨胀阻燃剂,通过热重分析(TG)、极限氧指数(LOI)、UL94测试、锥形量热仪以及扫描电镜(SEM)等测试手段,研究不同质量分数的P-N-Sn体系对PP复合材料阻燃抑烟性能及炭层结构的影响。实验结果表明,三嗪成炭剂-聚磷酸铵(TCA-APP)质量分数为26%时,阻燃PP复合材料在800℃时的残炭率提高了8.54%,最大热失重速率(MMLR)降低了44%,LOI由纯PP的18.8%提升至27.2%,UL94垂直燃烧等级达到V-0级,峰值热释放速率(pHRR)由599.79 kW/m²降至277.40 kW/m²,热释放总量(THR)由141.23 MJ/m²降至133.68 MJ/m²;ZHS的加入提升了P-N-Sn体系的阻燃和抑烟性能,添加0.5%的ZHS,残炭率提升至13.15%,SEM显示材料表面形成了致密的炭层,LOI达到32%,同时抑烟性能也得到了体现,热释放速率和总热释放量进一步降低...     

Improvement of thermal stability and flame retardancy of polypolypropylene composite modified by ZnO and MoO3 nanowires

Herein, zinc oxide (ZnO) and molybdenum trioxide (MoO₃) nanowires were prepared via the hydrothermal method. Then as-prepared ZnO and MoO₃ nanowires were fabricated to form ZnO/MoO₃ compound nanostructure. ZnO/MoO₃ compounds were incorporated into polypropylene (PP) with various loadings by melt blending. The D-Optimal mixing design in Design-Expert software was employed to study the effects of ZnO/MoO₃ compound content on flame retardancy and mechanical properties of nanocomposites. Information on performance of thermal stability and flame retardancy of PP/ZnO/MoO₃ nanocomposites was obtained through thermogravimetric analysis, cone calorimeter tests, and limiting oxygen index (LOI). The results reflected that the synthesized ZnO/MoO₃ compound possessed high thermal stability and flame retardancy. The addition of 15 wt % ZnO nanowires and 13 wt % MoO₃ nanowires increased LOI from 18.2 to 23.0%. Meanwhile, the tensile strength of the PP/ZnO/MoO₃ nanocomposite decreased by 13.8% and the elongation at break of the PP nanocomposite increased by 20.4% compared with pure PP. Response surface analysis results also indicated that the loading of ZnO/MoO₃ compound had an influence on the mechanical properties and flame retardancy of PP. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48312.     

Flammability and thermal behaviors of polypropylene composite containing modified kaolinite

Exfoliatied kaolinite (E‐Kaol) was prepared by intercalating DMSO and KAc into kaolinite successively followed by irradiation under ultrasonic. The modified kaolinite was then introduced to polypropylene (PP) by melt blending in order to improve the fire performance of the composite. The flammability and thermal behaviors of PP composite were analyzed by limit oxygen index, vertical burning test, cone calorimeter test, and thermal‐gravimetric analysis, respectively. The microstructure of PP composites was characterized by Fourier‐transformed infrared spectroscopy, X‐ray diffraction, and scanning electron microscope (SEM). It was demonstrated the presence of only 1 phr E‐Kaol could improve the LOI values of PP/MCAPP/ATH composite from 26.4 to 28.0, and decrease the peak value of heat release rate and smoke production rate of the PP/MCAPP/ATH by 60.7% and 39.1%, respectively, compared with that of PP sample. Morphology analysis by SEM showed that E‐Kaol in PP composite was beneficial to forming rigid and compact char structure. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41761.     

Flame Retardant Synergism of Hydroxy Silicone Oil and Al(OH)3 in EVA Composites

A synergistic effect on flame retardancy was found when hydroxy silicone oil (HSO) was incorporated into ethylene vinyl acetate/aluminum hydroxide (EVA/ATH) composite. The fire performance of EVA and EVA composites was studied by using limiting oxygen index (LOI), UL 94, and cone calorimeter test (CCT). Compared with the EVA/ATH binary composite, the LOI values of the EVA/ATH/HSO ternary composites at the same additive loading are all decreased. The CCT data indicated that the addition of HSO in EVA/ATH system not only reduces the heat release rate, but also prolonged the ignition time of the composite. Thermogravimetric analysis revealed that ATH accelerated the loss of acetic acid, but hydroxy silicone oil assisted to reduce ATH's accelerating effect.     

阻燃抑烟型聚乳酸/竹粉复合材料性能研究

采用模压成型法制备了氢氧化铝（ATH）、聚磷酸铵（APP）及APP+ATH阻燃型聚乳酸/竹粉(PLA/BF)复合材料,通过扫描电子显微镜考察了复合材料拉伸断面和燃烧后炭层的微观结构,并对其力学性能、热稳定性能和燃烧性能进行了测试。结果表明,阻燃剂的引入均降低了复合材料的力学性能,但显著提高了热稳定性,600 ℃时复合材料的残炭率分别达到了20.3 %、27.9 %和26.3 %;ATH对复合材料具有显著的抑烟效果,但抑热作用较APP要差,而ATH与APP复合阻燃剂使复合材料兼具较好的抑热作用和抑烟效果。     

Preparation of aluminum hydroxide/aluminum phosphinate flame‐retardant poly(vinyl alcohol) foam through thermal processing

A novel flame‐retardant poly (vinyl alcohol) (PVA) composite foam was prepared successfully through thermal processing, which was filled with high content of flame retardant, based on aluminum hydroxide (ATH) and aluminum phosphinate (AlPi) and using water as plasticizer and blowing agent. The flame‐retardant property and mechanism of the prepared foam matrix were studied by vertical burning test, limiting oxygen index (LOI), cone calorimeter, scanning electronic microscopy (SEM) and X‐ray photoelectron spectroscopy (XPS). The experimental results showed that the PVA/ATH/AlPi (1/1.2/0.05) composite achieved LOI value of 41% and UL94 V‐0 (3.2 mm) rate. The addition of ATH and AlPi into PVA matrix significantly decreased flammability of the composites, because a more compact and continuous char layer of the PVA/ATH/AlPi composite could be formed, due to the involvement of AlPi in the char‐forming reaction. Compared with the pure PVA sample, the peak heat release rate (PHRR) and total heat release (THR) of PVA/ATH/AlPi (1/1.2/0.05) composite were reduced by 76.5% and 58.2%, respectively. Built upon this PVA‐based foam matrix with good flame retardancy, the flame‐retardant PVA‐based foam was successfully prepared through thermal extrusion. In addition, the influence of water content on melt viscosity, foam structure and mechanical strength was also analyzed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42020.     

Synergistic effect of aluminum hydroxide and nanoclay on flame retardancy and mechanical properties of EPDM composites

The composites based on ethylene–propylene–diene monomer rubber (EPDM) with aluminum hydroxide (ATH), nanoclay, vulcanizing agent, and curing accelerator were prepared by conventional mill compounding method. The thermal stability and the flame retardant properties were evaluated by thermogravimetric analysis (TGA), limiting oxygen index (LOI), UL‐94 test, cone calorimeter, and smoke density chamber tests. The results indicated that the substitution of the nanoclay in the EPDM/ATH composites increased the 50% weight loss temperature and the LOI value, and reduced the peak heat release rate (pk‐HRR), the extinction coefficient (Ext Coef), the maximal smoke density (Dm), and the whole smoke at the first 4 min (VOF4) of the test specimens. The synergistic flame retardancy of the nanoclay with ATH in EPDM matrix could imply that the formation of a reinforced char/nanoclay layer during combustion prevents the diffusion of the oxygen and the decomposed organic volatiles in the flame. The mechanical properties of the composites have been increased by replacing more of the nanoclays into the EPDM/ATH blends. The best loading of the nanoclay in EPDM/ATH composites is 3 wt %, which keeps LOI in the enough value, the V‐0 rating in the UL‐94 test, and the improved mechanical properties with better dispersion and exfoliation of the nanoclays shown by transmission electron microscopy (TEM) micrographs. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2042–2048, 2013     

Co‐microencapsulation of ammonium polyphosphate and aluminum hydroxide in halogen‐free and intumescent flame retarding polypropylene

In this article, co‐microencapsulated ammonium polyphosphate (APP) and aluminum hydroxide (ATH) [M(A&A)] was prepared by using 4,4'‐diphenylmethane diisocyanate (MDI) and melamine (MEL) via in situ surface polymerization method. The chemical composition of M(A&A) was confirmed by Fourier transform‐infrared spectra (FT‐IR). Thermal behavior and surface morphology of M(A&A) were systematically analyzed by thermogravimetric analysis (TGA) and scanning electron microscope (SEM), respectively. Water solubility tests indicate that water solubility of M(A&A) decreases greatly than un‐microencapsulated ones. Besides, flame retardant properties of polypropylene (PP) compositing with M(A&A) were investigated by limiting oxygen index (LOI), vertical burning tests (UL‐94) and cone calorimeter. The results demonstrate the LOI value of PP composites is improved after combining with co‐microencapsulated flame retardants. Compared with PP/A&A, the peak heat release rate of PP/M(A&A) decreases from 210 to 120 kW/m² at the same flame retardant loading level. Moreover, in order to investigate the flame retardant mechanism, the char residue of PP composites after combustion was studied by optical photos, X‐ray photoelectron spectroscopy (XPS) spectra and FT‐IR. POLYM. COMPOS., 35:715–729, 2014. © 2013 Society of Plastics Engineers     

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.     

Preparation and flame retardancy of a novel flame‐retardant poly(ethylene‐co‐vinyl acetate)/aluminum hydroxide composites containing phosphorus

A novel flame‐retardant (SPDH) containing phosphorus was synthesized through the reaction of 10‐(2,5‐dihydroxyphenyl)‐9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide and synthesized intermediate product 3,9‐dichloro‐2,4,8,10‐tetraoxa‐3,9‐diphosphaspiro[5.5] undecane‐3,9‐dioxide, which was used for optimizing the flame retardancy of ethylene‐vinyl acetate copolymer (EVM) rubber/aluminum hydroxide (ATH) composites. The microstructure of SPDH was characterized and determined by Fourier transform infrared and nuclear magnetic resonance spectroscopy. Thermogravimetric analysis (TGA) showed that SPDH had good charring effect at high temperature (600°C). The flame retardancy of the optimized EVM/ATH composites by SPDH was investigated by limiting oxygen index (LOI), cone calorimeter, and UL‐94 vertical burning tests. A higher LOI value (29.8%) and better UL‐94 rating (V‐0) can be achieved for the optimized EVM/ATH composite (EVM‐7) than EVM/ATH composite without SPDH (EVM‐3) with the total loading of additives. The heat release rate decreased and residual mass increased gradually as the loading of SPDH increased for the optimized EVM/ATH composites. There existed distinct synergistic flame‐retardant effect between SPDH and ATH in EVM matrix. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Growth of ZnO nanowires on carbon fibers for photocatalytic degradation of methylene blue aqueous solutions: An investigation on the optimization of processing parameters through response surface methodology/central composite design

In this work, effects of hydrothermal (HT) synthesis method parameters, temperature, concentration and growth time, on the formation of zinc oxide nanowire structures on carbon fibers (ZnO NWs/CFs) were evaluated. Morphological, structural, photocatalytic properties were determined through scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV–Visible spectrophotometer. In addition, response surface methodology (RSM) and central composite design (CCD) were applied to optimize the hydrothermal synthesis parameters. The results pointed out that, the change in hydrothermal solution concentration (from 3.2 to 37 mM ZnNO_3·6H₂O) and process time (from 2.6 to 9.2 h) lead to the increase in thickness and decrease in aspect ratio of zinc oxide nanowires. Whereas, the temperature increases from 80 to 130 °C had a minute effect on the structure. ZnO nanowires with zincite structure were obtained for all processing conditions. Finally, photocatalytic activity of ZnO NWs/CFs on the degradation of aqueous methylene blue solution (MB) were recorded comparatively. ZnO NWs/CFs structure exhibited photocatalytic activity in the degradation of methylene blue (MB). The most effective structure was obtained at 120 °C, 30 mM Zn(NO₃)_2·6H₂O and 4 h HT synthesis parameters.