环保膨胀型阻燃PP母料的研制

以三聚氰胺聚磷酸(MPP)/季戊四醇(PT)为复配阻燃剂,氧化锌为催化协效剂,聚乙烯蜡为分散剂,并添加一定量载体树脂,制备了环保膨胀型阻燃聚丙烯(PP)母料,运用氧指数法、UL94垂直燃烧法、热失重分析法和扫描电子显微镜研究了阻燃PP母料的阻燃性能。结果表明:当MPP∶PT=2∶1且MPP与PT占母料总量的72%时,将该类母料添加到PP中制得的复合材料的综合性能最好;阻燃PP母料的最佳载体树脂为PP/PP-g-MAH(1/1),将25%PP/PP-g-MAH基阻燃PP母料添加到PP中,复合材料的阻燃等级可达到UL94V—0级。     

Chemical effects of cationic surfactant and anionic surfactant used in organically modified montmorillonites on degradation and fire retardancy of polyamide 12 nanocomposites

Three kinds of organically modified Na⁺-montmorillonites (OMMTs), including two kinds of octadecylammonium modified montmorillonite with different contents of octadecylammonium and a kind of sodium dodecylsulfonate (SDSo) modified montmorillonite, were used to prepare polyamide 12 (PA12)/OMMT nanocomposites. Effects of the modifiers on degradation and fire retardancy of PA12/OMMT nanocomposites were investigated. Acid sites formed in cationic surfactant modified MMT via Hoffman decomposition could accelerate degradation of PA12 at high temperature. However, catalytic effect of the acid sites on carbonization of the degradation products promoted char barrier formation, which reduced heat release rate (HRR). Higher content of cationic surfactant in OMMT is beneficial to fire retardancy of PA12 nanocomposites and the dispersion states of OMMT have assistant effects. In contrast, Na⁺-montmorillonite (Na-MMT) and anionic surfactant modified MMT (a-MMT) could not form acid sites on the MMT layers; in this case, fire retardancy of PA12/Na-MMT appears to have no improvement and PA12/a-MMT appears to have limited improvement.     

Thermal behaviors and flame‐retardancy of styrene–ethylene–butadiene–styrene–block copolymer containing various additives

The thermal behaviors and the flame‐retardancy of styrene–ethylene–butadiene–styrene–block copolymer containing various additives were studied. The combustion was measured by the Underwriter laboratory (UL) test and cone calorimeter test and thermogravimetric analysis and program‐mass spectroscopy were applied to analyze the thermal behaviors. The blend with halogen additives showed the best result in the UL test. However, the blend with red‐phosphorous was the best in the cone calorimeter test. As the styrene sequence in the copolymer tended to degradate at a lower temperature, the major scission products spouted out from the polymer surface originated from polystyrene. The shorter the ignition times of the blends with red‐phosphorous were, the lower the peak heat release rates were. It was an interesting phenomenon because it suggested that the chemical structure of the residue changed to more stable polymers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 156–161, 2007     

LLDPE/LDPE/Mg(OH)2/红磷高效阻燃体系的研究

采用线性低密度聚乙烯(LLDPE)、低密度聚乙烯(LDPE)作为阻燃体系的主体，用表面处理过的氢氧化镁(Mg(OH)2)作主阻燃剂，微胶囊化红磷作阻燃增效剂，重点探讨了Mg(OH)2和微胶囊化红磷的阻燃效果。结果表明：Mg(OH)2与红磷并用具有良好的协同效应，是LLDPE／LDPE的高效阻燃体系。     

十溴二苯乙烷协同三氧化二锑阻燃聚对苯二甲酸丁二醇酯

以十溴二苯乙烷(DBDPE)和三氧化二锑(Sb2O3)作为复合阻燃剂，对聚对苯二甲酸丁二醇酯(PBT)进行改性。研究了复合阻燃剂对PBT的燃烧性能、热稳定性能和力学性能的影响，并其对阻燃机理进行了探讨。结果表明，阻燃剂DBDPE／Sb2O3对PBT具有良好的阻燃效果，热稳定性能基本不变，而其拉伸强度、冲击强度和弯曲强度都随阻燃剂用量的增加先增后降，阻燃剂的用量不宜过大。     

The effect of CO2 dissolved in a diesel fuel on the jet flame characteristics

This paper is concerned with an experimental study of the jet diffusion flame characteristics of fuel containing CO₂. Using diesel fuel containing dissolved CO₂ gas, experiments were performed under atmospheric conditions with a diesel hole-type nozzle of 0.19 mm orifice diameter at constant injection pressure. In this study, four different CO₂ mass fraction in diesel fuel such as 3.13%, 7.18%, 12.33% and 17.82% were used to study the effect of CO₂ concentration on the jet flame characteristics. Jet flame characteristics were measured by direct photography, meanwhile the image colorimetry is used to assess the qualitative features of jet flame temperature. Experimental results show that the CO₂ gas dilution effect and the atomization effect have a great influence on the flame structure and average temperature. When the injection pressure of diesel fuel increased from 4 MPa to 6 MPa, the low temperature flame length increased from 18.4 cm to 21.7 cm and the full temperature flame length decreased from 147.6 cm to 134.7 cm. With the increase of CO₂ gas dissolved in the diesel fuel, the jet flame full length decreased for the jet atomization being improved greatly meanwhile the low temperature flame length increased for the CO₂ gas dilution effect; with the increase of CO₂ gas dissolved in the diesel fuel, the average temperature of flame increases firstly and then falls. Experimental results validate that higher injection pressure will improve jet atomization and then increased the flame average temperature.     

磷硅阻燃剂协同效应及其应用

介绍了磷系阻燃剂、硅系阻燃剂及其协同阻燃体系的阻燃机理,回顾了磷硅协同阻燃剂在环氧树脂中的应用情况,并对其应用前景进行了展望.     

梭式窑装载密度较大时氧化焰烧成新途径

通过分析氧化焰条件对梭式窑使用上的影响,阐述了由于文丘里喷嘴自身局限性,有必要对烧成系统进行改造,从结构上保证窑炉的气密性,并利用高速喷嘴的特点,由此获得在码装密度较大时氧化焰烧成的方式和方法。     

环保型阻燃聚丙烯的研制

应对欧盟RoHS环保要求,对环保型阻燃聚丙烯的研制进行了研究;并探讨了六溴环十二烷和三氧化二锑对PP材料阻燃性及物理性能的影响,得到了一种性能优良的环保型阻燃PP。     

电缆用高阻燃耐热软质PVC的制备及性能研究

以软质PVC为基体,选用氢氧化铝-氢氧化镁(ATH/MDH)为复配阻燃剂、硼酸锌(ZB)为阻燃协效剂及钙锌材料为复合热稳定剂(Ca-Zn),通过共混法对PVC进行改性,制备PVC/ATH/MDH、PVC/ATH/MDH/ZB及PVC/ATH/MDH/ZB/Ca-Zn等软质PVC复合电缆料。分析3种电缆料的阻燃性能、拉伸性能及热稳定性。结果表明:相较纯软质PVC,PVC/ATH/MDH与PVC/ATH/MDH/ZB的阻燃性能提高,拉伸性能显著下降,且热稳定性改善不明显。而PVC/ATH/MDH/ZB/Ca-Zn的阻燃性能显著提升,与纯软质PVC相比,其极限氧指数(LOI)增加34.90%,烟密度等级下降29.50%,复合材料的炭层更连续且致密;PVC/ATH/MDH/ZB/Ca-Zn的拉伸强度和断裂伸长率分别提高1.78%和2.48%。Ca-Zn的添加提高软质PVC的残炭率,热稳定性增强。PVC/ATH/MDH/ZB/Ca-Zn的综合性能最佳。