高温加成硫化硅橡胶研究

本文研究了含氢硅油在铂催化剂存在下,对乙烯基硅橡胶的高温加成硫化;选择了不同的化合物作抑制剂,初步解决了高温加成硫化胶料的焦烧问题。试验表明,高温加成硫化硅橡胶具有良好的物理机械性能,突出的透明性和自熄性,胶料具有优良的常压热空气硫化性能。采用高温加成硫化硅橡胶进行连续热空气硫化,制造工业和医用硅胶管等压出制品已获得实际应用。     

加成型高温硫化硅橡胶及其在S—25型绝缘子制造上的应用

该绝缘子是采用加成型高温硫化硅橡胶制备的。该胶系端乙烯基聚硅氧烷生胶,填加一定量的填料,含氢硅油和铂触媒,在高温下模压成型。胶料以双组份形式,使用前将等量的两组份混炼均匀,模压制品由于采用加成硫化体系,制品无须二段硫化。采用     

高性能阻燃液体硅橡胶的制备

以乙烯基硅油为基础聚合物、自制低含氢硅油为交联剂、气相法白炭黑为补强填料、自制铂化合物为催化剂,加入一定量的阻燃剂,制备了性能优良的阻燃液体硅橡胶。讨论了氢氧化铝、苯并三氮唑对液体硅橡胶阻燃性、力学性能和硫化特性的影响。     

铂催化剂用量对加成型液体硅橡胶硫化行为的影响

采用流变学方法研究了铂催化剂用量对加成型双组分室温硫化(RTV-2)液体硅橡胶在聚氯乙烯(PVC)表皮上硫化行为的影响,并通过调整硅橡胶中铂催化剂的用量,解决了搪塑模具制备过程中因RTV-2硅橡胶与PVC表皮中P元素反应所导致的硅橡胶硫化不完全及花纹复制率低的问题。结果表明,额外添加0. 5%～1. 0%的铂催化剂后,硅橡胶在PVC表皮上能完全硫化并形成清晰花纹。     

甲基乙烯基硅橡胶并用体系研究

并用两种乙烯基含量不同的甲基乙烯基硅橡胶，添加适量含氢硅油，同时采用过氧化物和铂催化加成这两种硫化方式。可以得到高撕裂乙烯基硅橡胶。结果表明，当乙烯基质量分数为0．09％和0．13％的生胶并用比为50／50时，其撕裂强度比单独使用两种生胶时分别提高了46．9％和21．7％；两种硫化体系并用时，性能有了显著提高，超过了单独使用一种硫化方式的性能。     

甲基乙烯基硅橡胶硫化体系综述

分析了不同硫化体系对甲基乙烯基硅橡胶性能影响的意义。简单介绍了甲基乙烯基硅橡胶高温硫化机理,比较了不同硫化体系之间的优缺点,总结了不同种类硫化剂对甲基乙烯基硅橡胶硫化性能的影响。     

中温硫化陶瓷化硅橡胶的制备与性能

以混入硅灰石的甲基乙烯基硅橡胶为基质,加入A/B双组分硫化剂,制备了可用于中温(70℃)硫化的陶瓷化硅橡胶,并研究了其微观形貌和性能。结果表明,硅橡胶完全可以在70℃进行硫化,适量的铂化合物对硅橡胶的成瓷和阻燃效果具有积极作用,在800℃下烧蚀可形成致密的陶瓷体。当A组分用量为3份(质量)时效果最佳,硅橡胶的拉伸强度达到7.8 MPa,极限氧指数为34%,陶瓷体质量残留率和弯曲强度分别达到69%和15.6 MPa;A组分过量时虽然硅橡胶的力学性能变化不大,但阻燃和成陶瓷化效果均下降。     

铂催化剂/硫化剂在固体硅橡胶中的应用

以甲基乙烯基硅橡胶生胶、铂/烯丙基硅氧烷配合物、硫化促进剂、含氢硅油、抑制剂为原料,制成了固体硅橡胶用透明双组分铂催化剂/硫化剂(PL-10A/TM-10B),并将其应用在固体硅橡胶中;比较了加成硫化体系和过氧化物硫化体系对硅橡胶力学性能及其产品生产成本的影响.结果表明,与过氧化物硫化硅橡胶相比,当硫化剂用量相近时,采用PL-10A/TM-10B的加成硫化固体硅橡胶的拉伸强度和撕裂强度更高,但拉伸永久变形更大.在加成硫化体系中,催化剂PL-10A的用量对硅橡胶的力学性能影响不大;对产品的硫化周期有较大影响,PL-10A用量越大,硫化周期越短.在PL-10A用量相同时,随硫化剂TM-10B用量的增加,硅橡胶的拉伸强度和撕裂强度先增后降,在TM-10B质量分数为1.0%时达到极大值;拉伸永久变形则逐渐减小.采用PL-10A/ TM-10B的加成硫化固体硅橡胶符合GB/T 16175-1996医用有机硅材料生物学评价试验方法的要求,可用于生产卫生要求较高的制品.采用PL-10A/ TM-10B的加成型固体硅橡胶因生产效率而降低单位产品生产成本,具有较强的竞争优势.     

室温硫化泡沫硅橡胶的研究

以α ω -二羟基聚二甲基硅氧烷 (1 0 7硅橡胶 )、含氢硅油、沉淀法白炭黑为主要原料 ,制成了适合于灌封的双组分室温硫化 (RTV - 2 )泡沫硅橡胶。讨论了 1 0 7硅橡胶粘度、含氢硅油和铂催化剂用量对RTV - 2泡沫硅橡胶发泡性能、硫化性能及阻燃性能的影响。结果表明 ,随着 1 0 7硅橡胶粘度、含氢硅油和催化剂用量的增加 ,泡沫的发泡系数增大 ,泡孔尺寸逐渐减小 ,泡孔的闭孔率增加 ,泡孔的分布趋于均匀细密、硬度降低、弹性增加 ;当 1 0 7硅橡胶粘度为 3～ 5Pa·s、含氢硅油和铂催化剂的用量分别为 3份和 5～ 8份时 ,泡沫硅橡胶的发泡系数为 2 5～ 3 0 ,且流动性好     

白炭黑对硅橡胶耐热性能的影响

考察了白炭黑种类、用量以及表面处理对高温硫化硅橡胶耐热性能的影响。结果表明，气相法白炭黑会降低耐热性能，而经过表面处理后，可以在一定程度上改善耐热性能。白炭黑影响硅橡胶耐热性能的主要原因是表面存在活性硅羟基。     

Melamine polyphosphate/silicon‐modified phenolic resin flame retardant glass fiber reinforced polyamide‐6

The halogen‐free flame retardance of glass fiber reinforced polyamide‐6 (PA6) is an everlastingly challenge due to well‐known wick effect. In this research, a novel system composed of a nitrogen–phosphorous flame retardant, melamine polyphosphate combined with a macromolecular charring agent, silicon‐modified phenolic resin (SPR), was employed to flame‐retard glass fiber reinforced PA6. It exhibited obvious synergistic effect between the two components at a proper ratio range. The flame retardance of the composites can be remarkably improved due to the increased amount and improved thermal stability of the produced char. The flame resistance tests indicated that the synergism system with an optimized ratio achieved V0 (1.6 mm) rating of UL94, 25.2% of Limited Oxygen Index, and only 338.2 W/g of the heat release peak rate. The corresponding synergistic mechanisms were investigated by the characterizations including the thermal gravimetric analysis, carbonation test, and the char morphology observation. It confirmed that the introduced SPR could accelerate the carbonation of PA6 resin, which was in favor of the construction of denser and more continuous charring structure. In addition, the flame retardant materials also indicated the acceptable mechanical properties, showing the advantages in the overall performance. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Increase in flame retardance of glass‐epoxy laminates without halogen or phosphorous compounds by simultaneous use of incombustible‐gas generator and charring promoter

Highly flame‐resistant glass‐epoxy laminates without flame‐retarding additives such as halogen and phosphorous compounds have been developed to overcome environmental problems caused by these additives. The laminates consist mainly of a self‐extinguishing epoxy‐resin compound (phenol aralkyl), an incombustible‐gas generator (amino‐triazine‐novolac hardener: ATN hardener), and inorganic materials such as a charring promoter (zinc molybdate on talc: ZMT) and a limited amount of harmless metal hydroxide (aluminum trihydroxide: ATH). They are highly flame‐resistant and have other beneficial characteristics, including soldering‐heat resistance, humidity resistance, electronic properties, and processing advantages. These qualities make them applicable enough to replace the FR‐4 type printed wiring boards (PWBs) that are widely used today. Simultaneously using the ATN hardener and ZMT in the laminates, including the epoxy‐resin compound and ATH, greatly improved their flame retardance. We then reduced the amount of ATH to obtain even better flame retardance in the laminates. This reduction of the ATH, consequently, improved other practical characteristics such as soldering‐heat resistance, humidity resistance, and electronic properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3367–3375, 2006     

HIPS/纳米蒙脱土复合材料的研究

添加不同种类，不同数量的纳米蒙脱土，混炼制得HIPS／纳米蒙脱土复合材料，以改善高抗冲聚苯乙烯（HIPS）的性能，测试了其力学性能，热稳定性性。结果表明，添加3％烘干的蒙脱土Cloisite 30A的HIPS／纳米蒙脱土复合材料具有较好的综合力学性能，可作为工程塑料使用；HIPS／纳米蒙脱土复合材料的热稳定性与阻燃性有所改善，添加5％烘干的蒙脱土Cloisite 15A的HIPS／纳米蒙脱土复合材料具有较好的阻燃性。     

三聚氰胺对RTV硅橡胶阻燃性能的影响

研究了三聚氰胺（ＤＣＤＡ）对ＲＴＶ硅橡胶阻燃性能的影响。结果表明,ＣＤＤＡ对ＲＴＶ硅橡胶具有较好的阻燃作用,当ＤＣＤＡ用量达到４０ｇ时,ＲＴＶ硅橡胶能自熄;但由于二者相容性左,大量添咖ＤＣＤＡ会导致ＲＴＶ硅橡胶力学性能急剧下降。     

Synthesis and characterization of a novel charring agent and its application in intumescent flame retardant polypropylene system

A novel halogen‐free charring agent bi(4‐methoxy‐1‐phospha‐2, 6, 7‐trioxabicyclo [2.2.2]‐octane‐1‐sulfide) phenylphosphate (BSPPO) was synthesized from phenylphosphonic dichloride (PPDC), and 4‐hydroxymethyl‐1‐phospha‐2, 6, 7‐trioxabicyclo[2.2.2]‐octane‐1‐sulfide (SPEPA) which was synthesized from pentaerythritol and thiophosphoryl chloride in this article. The structure of BSPPO and SPEPA was characterized by Fourier transform infrared (FTIR), ¹H‐NMR, ¹³C‐NMR, and ³¹P‐NMR. Combined with ammonium polyphosphate (APP) and melamine pyrophosphate (MPP), the flame retardance and dripping resistance of BSPPO added in polypropylene (PP) were investigated. The fire performance of the flame retardant PP system was investigated by limiting oxygen index (LOI), vertical burning test (UL‐94), and cone calorimeter. The thermal stabilities of the composites were studied by thermogravimetric analysis (TGA). The flame retardance mechanism was investigated by FTIR and scanning electronic micrograph (SEM). The mechanical properties and water solubility were also investigated. The residue of BSPPO is 40.6% at 600°C, which indicates BSPPO has excellent charring ability. The char residue of the polypropylene intumescent flame retardant (PP‐IFR) system is 22% at 600°C, which suggests that the flame retardation synergy of APP, BSPPO, and MPP is good. With the optimum formulation, the LOI of the IFR‐PP system is 32.0, and the UL‐94 is V‐0 rating. The heat release rate (HRR), total heat release (THR), smoke production rate (SPR), total smoke production (TSP), and mass loss rate (MLR) of IFR‐PP with the optimum formulation decrease significantly comparing to pure PP from cone calorimeter analysis. The FTIR and SEM results indicate that the char properties and the char yield have direct effect on the flame retardance and antidripping behaviors. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

A novel flame retardant of spirocyclic pentaerythritol bisphosphorate for epoxy resins

A novel flame retardant for epoxy resins, bisdiglycol spirocyclic pentaerythritol bisphosphorate (BDSPBP) was synthesized from the reaction of diglycol with spirocyclic pentaerythritol bisphosphorate diphosphoryl chloride, which was obtained from the reaction of phosphoryl chloride with pentaerythritol. Flammability of the cured epoxy resin systems consisted of diglycidyl ether of bisphenol A (DGEBA), low‐molecular‐weight polyamide and BDSPBP are investigated by vertical burning test (UL‐94) and limiting oxygen index test (LOI). The results indicate that BDSPBP has good flame retardance on epoxy. The thermogravimetric analysis (TGA) shows that the epoxy resin containing BDSPBP has a high yield of residual char at high temperatures, indicating that BDSPBP is an effective charring agent. From the SEM observations of the residues of the flame retardant systems burned, the compact charred layers can be seen, which form protective shields to protect effectively internal structure, and inhibit the transmission of heat and heat diffusion during contacting fire. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4978–4982, 2006     

A quantitative evaluation method of the barrier property of the residue for flame retardant polymers

To investigate the flame retardant properties and mechanisms of those fire retardant polymer systems that mainly depend on the produced protective char shields, quantitative analysis for the barrier quality of the char layer is important but still a challenge. In the present article, a novel and simple characterization method based on atmosphere permeability is proposed to quantitatively evaluate the barrier property: an incombustible fabric carrier coated with the flame retardant polymer solution, is carbonized at high temperature to make the produced char residue adhered to the fabric. As the interfibrous gaps are filled and closed by the chars, the atmosphere permeability of the heated fabric decreases compared with that of original one. Their difference value can really reflect the contribution of the charring residue to the barrier property. This method combined with other characterizations including residue morphology observation, vertical burning test, limiting oxygen index, and calorimetric analysis, is very helpful to reveal the correlation between the flame retardance and barrier property of the char residue, evaluate the flame retardant efficiency in the condense phase, and estimate the corresponding flame retardant mechanisms. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45102.     

Acidic buffer mechanism of cyclotriphosphazene and melamine cyanurate synergism system flame retardant epoxy resin

In this research, a new synergistic mechanism based on an acid‐buffer action for cyclotriphosphazene (CPZ)/melamine cyanurate (MCA) flame retardant epoxy resin (EP) was proposed. This mechanism broke through the conventional well‐recognized phosphorus–nitrogen interaction one. It revealed that CPZ had not only acid‐catalytic charring but also acid‐catalytic degrading effect on EP. The former that occurs in higher temperature range to improve the flame resistance in the condensed phase is a mechanism generally accepted for the phosphorus flame retardant, but the later that occurs in lower temperature range to deteriorate the flame retardance is usually ignored by the people. For CPZ/MCA flame retardant EP, the produced organic base from decomposed MCA can neutralize the acids from CPZ. Decline of the acidity effectively weakened the acid‐catalytic effect, and reduced the volatiles release rate of the degraded resin in the initial stage, thus slowing down the combustion in the gaseous phase. With increasing temperature, the neutralized products were converted to the phosphorus‐containing acids again to promote the formation of the chars. A series of characterizations such as vertical burning test, X‐ray photoelectron spectra, micro‐scale combustion calorimetry, thermogravimetric, and differential thermogravimetric analysis of the flame retardant materials and the pH value detection of the corresponding carbonation products were performed to investigate the acid‐buffer mechanism. The experimental results including no N? P forms in the condensed phase obviously improved flame retardance and increased degradation temperature of CPZ/MCA/EP compared with CPZ/EP, as well as the enhanced pH value of the former carbonation residue confirmed the above mechanism. POLYM. ENG. SCI., 55:1046–1051, 2015. © 2014 Society of Plastics Engineers     

Synergistic effect of a novel charring agent with ammonium polyphosphate on flame retardancy and thermal degradation of acrylonitrile‐butadiene‐styrene copolymer

A novel charring agent poly(1,3‐propylene terephthalamide) (PPTA) was synthesized and characterized by Fourier transform infrared spectroscopy and ¹H nuclear magnetic resonance. This novel charring agent combined with ammonium polyphosphate (APP) was adopted as an intumescent flame retardant (IFR) to impart flame retardance and dripping resistance to acrylonitrile‐butadiene‐styrene copolymer (ABS). Flammability and thermal behaviors of the treated ABS were investigated by limiting oxygen index, vertical burning test and thermogravimetric analysis. The results showed that the IFR with the novel charring agent had both excellent flame retardant and anti‐dripping abilities for ABS. The thermogravimetric analysis curves indicated that there was a synergistic effect between PPTA and APP, which greatly promoted the char formation of IFR‐ABS composites. Meanwhile, the thermal degradation mechanism of PPTA and APP/PPTA was characterized using thermogravimetric analysis/infrared spectrometry. The results demonstrated that APP changed the thermal degradation behavior of PPTA and reacted with PPTA to form a crosslinked structure. Additionally, the structure and morphology of char residues were studied by Fourier transform infrared spectroscopy and scanning electron microscopy. Copyright © 2011 Society of Chemical Industry     

阻燃PET的热降解行为研究

利用TG—DTG方法，研究了不同配比阻燃PET在N2气氛下的热降解行为。结果发现，阻燃则能显著减缓PET的分解速率，提高PET分解后形成的残余物的稳定性，使化学成炭质量得到改善；阻燃刑的加入使体系的成炭化学反应过程提前，显示了较好的协效作用，有利于残余物的稳定，提高其阻燃性能。