核壳结构和层状结构改性剂对PC阻燃性能的影响

用自制的含蒙脱土、纳米SiO2、纳米CaCO3的改性剂与聚碳酸酯(PC)混合,通过锥形量热仪测试了PC合金的阻燃性能。结果发现PC合金的放热速率、质量损失速率、生烟速率等均显著降低,燃烧时间增加,说明改性剂对PC具有阻燃性。通过分析PC合金的燃烧性能,探讨了其可能的阻燃机理。研究表明,乳液聚合法制备的含有无机粒子的PC合金是一种阻燃效能高、环境友好且实际可行的阻燃体系。     

核壳结构和层状结构改性剂的制备及其对PC性能的影响

通过乳液聚合法制备含有纳米SiO2或纳米CaCO3的核壳结构改性剂、含有蒙脱土的层状结构改性剂,并将这些改性剂与聚碳酸酯(PC)混合,考察其对PC性能的影响。结果表明,加入改性剂后,PC的加工性能得到很好的改善,冲击强度提高30％～50％,拉伸强度和弯曲强度基本不降低。改性剂还使PC的储能模量降低,损耗模量提高。同时,用扫描电镜对PC及其合金的拉伸和冲击断面进行观察,并观察了改性剂粒子在PC合金中的分散情况,从微观上解释了PC合金力学性能的改变。     

磷酸酯与纳米蒙脱土协同阻燃PC/ABS合金的研究

研究了多芳基磷酸酯PX220与纳米蒙脱土复配阻燃剂对聚碳酸酯(PC)/丙烯腈-丁二烯-苯乙烯(ABS)合金的阻燃性能、热失重行为、力学性能及热变形温度的影响;并采用锥形量热仪对合金材料的燃烧性能进行测定。结果表明:PX220添加量为10份,纳米蒙脱土添加量2份时,PC/ABS合金的极限氧指数达到29%,燃烧性能达到UL 94V-0级。锥形量热仪分析结果表明:复配阻燃PC/ABS合金的热释放速率峰值、平均热释放速率、总释放热、平均有效燃烧热和平均质量损失速率都大幅下降,说明PX220与纳米蒙脱土具有非常好的协同阻燃作用。     

PC/ABS阻燃合金的开发及性能研究

利用双螺杆挤出机制备了聚碳酸酯/丙烯腈-丁二烯-苯乙烯共聚物(PC/ABS)共混合金,并以磷酸三苯酯/热塑性酚醛树脂(TPP/TPPFR)复配体系作为膨胀型阻燃剂(IFR)对其进行阻燃改性。通过拉伸、弯曲、冲击强度测试考察了PC/ABS阻燃合金的力学性能;通过热变形温度(HDT)和熔体流动速率(MFR)测试考察了合金的耐热性能和加工性能;通过极限氧指数(LOI)和垂直燃烧测试考察了合金的阻燃性能。结果表明:当PC与ABS的质量比为4:1,复配阻燃剂TPP/TPPFR的质量比为1:1、添加量为11份时,可得到综合性能优异的PC/ABS阻燃合金。     

阻燃聚碳酸酯耐候性能研究

以阻燃聚碳酸酯材料为研究对象,探讨了不同种类抗冲击改性剂、不同种类阻燃剂、不同种类紫外线吸收剂、不同种类抗水解助剂对阻燃聚碳酸酯材料耐候性能的影响。结果表明:添加以硅橡胶为核的MSiA抗冲击改性剂的阻燃聚碳酸酯材料耐光性能和耐水性能均最好;添加磷腈类阻燃剂SPB-100的阻燃聚碳酸酯材料耐光性能与耐水性能均最好;添加氰基丙烯酸酯类紫外线吸收剂Uvinul 3030的阻燃聚碳酸酯材料耐光性能最好;添加聚合碳化二亚胺抗水解剂Stabaxol P100的阻燃聚碳酸酯材料耐水性能最好。     

磷酸酯与无机阻燃剂协同阻燃PC/ABS合金研究

研究了多聚芳基磷酸酯PX220分别与纳米蒙脱土和硼酸锌复配对聚碳酸酯/丙烯酸-丁二烯-苯乙烯共聚物(PC/ABS)合金的阻燃性能、热稳定性、力学性能及热变形温度的影响。结果表明:用2份纳米蒙脱土和3份硼酸锌分别与10份PX220复配制备阻燃PC/ABS,其氧指数分别达到28%和32%,燃烧性能达到UL94 V-0级。扫描电镜和热重分析表明,复配阻燃剂阻燃PC/ABS合金的炭层能有效隔绝热量的传递,阻止PC/ABS合金热降解,PC/ABS合金热稳定性明显提高。     

不同聚合物材料的单体燃烧性能研究

采用单体燃烧试验法研究了8种不同聚合物保温材料的燃烧增长速率指数、热释放量、烟气生成速率指数、产烟量等燃烧性能,并根据它们进行级别判定,同时对它们的燃烧反应过程进行了分析探讨。结果表明,聚苯乙烯和聚氨酯保温材料均属于E级材料,而橡塑保温材料属于可燃的D级材料,但其烟气中含有较多的低分子聚合物。阻燃改性处理后,它们的燃烧增长速率指数大幅降低,阻燃效果显著。酚醛树脂属于B级材料,烟气产量相对较小,表面包覆钢材后可以更好地达到阻燃的效果。     

六苯氧基环三磷腈对PC/ABS合金的阻燃作用

通过极限氧指数测定(LOI)、垂直燃烧试验和锥型量热分析研究了六苯氧基环三磷腈(HPTCP)对聚碳酸酯/丙烯腈-苯乙烯-丁二烯共聚物(PC/ABS)合金的阻燃作用。结果表明:HPTCP对PC/ABS具有良好的阻燃效果。当添加量为15%时,阻燃PC/ABS的LOI为25.0%,阻燃等级达FV-0,并且与未阻燃PC/ABS相比,燃烧时的热释放速率、总热释放量、最高热释放速率、平均热释放速率,平均有效燃烧热和质量损失明显降低;热重分析表明,HPTCP对PC/ABS合金的热稳定性影响较小。热重和残余物分析结果表明,HPTCP主要是通过凝聚相产生阻燃作用,HPTCP的添加可有效抑制PC/ABS的分解,促进它成炭,形成膨胀性炭层,该炭层通过隔热、隔氧及阻止PC/ABS分解产物的挥发而产生阻燃作用。     

高熔融流动速率阻燃聚碳酸酯的优点

据《PolmperDegradationStabiity》1996，54（2－3）181——188报导，美国道化学公司的塑料公司著述聚碳酸酯（PC）有某些阻燃特性，且有好的物理和机械性能，然而，聚碳酸酯树脂由于有高的粘度，所以不像某些苯乙烯材料一样容易加工。他们通过进一步的研究开发了容易流动（高的流动速率MFR）的阻燃聚碳酸酯（IRPC）树脂。这种不寻常的高MFR聚碳酸酯与通常的IRPC比较，它含有较低的阻燃剂水平，有利于保持聚碳酸酯基础树脂原来的物理和机械性能，不会牺牲最终产品的耐燃性能。使用高MFR聚碳酸酯树脂可改善加工性能，使可能的热降解…     

PA6/蒙脱土复合材料的炭层结构对阻燃性能的影响

采用熔融插层法制备了含有无机蒙脱土(MMT)和有机蒙脱土(OMMT)的PA6(尼龙6)/MMT和PA6/OMMT复合材料,并通过锥形量热仪评价了复合材料的阻燃性能;采用数码相机、扫描电镜(SEM)观察了燃烧残余物的宏观、亚微观和微观结构。结果表明,OMMT能明显降低复合材料的热释放速率和质量损失速率,PA6/OMMT纳米复合材料燃烧中形成的炭渣具有特殊的皮层-蜂窝层复合的亚微观结构,并在微观上具有网络结构,二者共同作用构成了有效的阻隔层,降低了材料的可燃性。     

The performance of sulfonate salt-containing polycarbonate products in flammability testing

Sulfonate salts are commonly employed together with other standard flame retardant (FR) additives to improve FR performance in polycarbonate resins. The structure and loading level of the salt and the synergistic FR additives determine the level of FR performance. The salts show varying levels of FR effetiveness as measured by different flammability test methods. In this paper, two common sulfonate salt additives in Lexan polycarbonate resins are discussed. FR effectiveness measured by UL94, OSU and cone calorimeter flammability testing, physical and mechanical properties, and processability of the thermoplastic products are compared. TGA-IR studies and the ability to predict FR performance are also discussed.     

原位聚合法PS／蒙脱土复合材料燃烧性能的研究

采用原位聚合法分别制备了聚苯乙烯／有机蒙脱土（PS／OMMT）复合材料和聚苯乙烯／无机蒙脱土（PS／MMT）复合材料、用锥形量热仪测量测试了复合材料的燃烧性能，结果发现复合材料的热释放速率、质量损失速率、生烟速率等均显著降低，说明复合材料具有阻燃性。通过分析材料的燃烧性能和燃烧残余物，探讨了其可能的阻燃机理。还考察了原位聚合法对聚合转化率的影响。研究表明原位聚合法制备的PS／蒙脱土复合材料是一种阻燃效能高、环境友好且实际可行的阻燃体系。     

Flammability of polyesters

The flammabilities of a series of polyesters, varying both the diol length and the degree of aromaticity of the diacid units were evaluated using cone calorimetry. Addition of inorganic additives, copolymerization with sulfoisophthalate ionomeric units and with the phosphorous flame retarding agent, phospholane, were also examined. A strong, linear relationship between the polymer carbon:hydrogen ratio and various flammability indicators was established. The phospholane was demonstrated to produce only a modest reduction in flammability, whereas the isomeric comonomer produced an unexpectedly strong reduction in all aspects of flammability tested. Addition of inorganic modifiers resulted in varied, and relatively modest changes in polyester flammability.     

聚酰胺6无卤阻燃改性的研究进展

针对聚酰胺6（PA6）易燃性和卤系阻燃改性污染性的问题,介绍了未改性PA6的燃烧机理和阻燃机理,综述了近年来PA6材料无卤阻燃改性的研究进展,包括单一无卤阻燃改性和协效无卤阻燃改性两大类,其中单一无卤阻燃改性又分为有机阻燃改性（磷系阻燃改性、氮系阻燃改性、硅系阻燃改性）、无机金属阻燃改性、纳米阻燃改性,最后对PA6无卤阻燃改性的前景作出了展望。     

Transparent notch width sensitivity improvers for polycarbonate

Notch width sensitivity, a serious deficiency of polycarbonate, can be improved by addition of 3–10 percent of specially modified methacrylate-butadiene-styrene (MBS) graft polymers. Blends of these modifiers with polycarbonate are transparent, in contrast to polycarbonate blends with previously reported notch width sensitivity improvers which are opaque. The synthesis of these modifiers is described together with physical properties of polycarbonate/modifier blends.     

Evaluation of the smoke and flammability characteristics of polymer systems

Using Oxygen Index and the XP-2 test to measure flammability and smoke characteristics, a broad spectrum of thermoplastic and thermoset polymers, both commercial and experimental, were investigated to elucidate the effect of structure on fire properties. In general, polymers with aliphatic backbones are very flammable, but their tendency to generate smoke is minimal. The addition of flame retardants, especially halogen compounds, while reducing their tendency to burn, increases the evolution of smoke. Halogen-containing polymers are usually non-flammable, with high Oxygen Indices, but display high smoke generation. Polymers containing an aromatic group in the side chain, such as polystyrene, are both highly flammable and high smoke producing. However, polymers with the aromatic group in the main chain, such as polysulfone, polycarbonate and polyphenylene oxide, are intermediate in both Oxygen Index and smoke generation. After investigation of the various test methods available, it is concluded that no one test will be satisfactory to measure the flammability characteristics of polymers and that a combination of methods must be used.     

An experimental study of flammability limits of LPG/air mixtures

The liquefied petroleum gas (LPG) is generally considered to be eco-friendly viable fuel not only in domestic sector but also for transport sector. The inhibition of LPG-air premixed flames is a very important practical problem that has received relatively little attention. This paper is concerned with experimental determination of the flammability limits of LPG-air mixture. The standard procedure suggested by US Bureau of mines has been adopted for the present studies for determining the flammability limit of LPG-air mixture. The lower flammability limit (LFL) is found to be 1.81% and upper flammability limit (UFL) is 8.86% of LPG for upward propagation of flame. Whereas, for downward propagation of flame, the LFL and UFL are 1.87 and 7.69% of LPG, respectively. The nitrogen dilution effects on the flammability limits have been explored, which is presented on a flammability limit plot. It is believed that these data will be very useful for developing fire extinguishers and other combustion devices.     

Flammability of polystyrene layered silicate (clay) nanocomposites: Carbonaceous char formation

Polymer layered‐silicate (clay) nanocomposites have not only the unique advantage of reduced flammability, but also improved mechanical properties. This is a key advantage over many flame retardants, which reduce flammability but also reduce the mechanical properties of the polymer. In our efforts to further understand the mechanism of flame retardancy with polymer‐clay nanocomposites, we investigated the effect of the clay, the loading level and polymer melt viscosity on the flammability of polystyrene‐clay nanocomposites. The nanoscale dispersion of the clay in the polymer was analysed by wide‐angle X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Cone calorimetry and gasification studies were used to evaluate the flammability of these nanocomposites. There were major reductions in peak heat release rates (HRRs), and increased carbonaceous char formation, for these nanocomposites. It was determined that while the viscosity of the PS nanocomposite played a role in lowering the peak HRR, the clay loading level had the largest effect on peak HRR. Finally, it was found that clay catalysed carbonaceous char formation, and the reinforcement of the char by the clay was responsible for the lowered flammability of these nanocomposites. Published in 2002 by John Wiley & Sons, Ltd.