裂解气相色谱/质谱联用研究防焦剂CTP的热裂解

采用裂解气相色谱/质谱联用法对防焦剂CTP的热裂解行为进行研究,并对部分热裂解产物的质谱碎裂机理进行探讨。结果表明:防焦剂CTP热裂解适宜条件为温度300℃,时间0.2 min,方式单纯瞬间裂解,固体样品直接进样;不同产地产品的裂解产物具有一致性,热稳定性好;裂解产物共10余个,主峰为原分子,次强峰为邻苯二甲酰亚胺。解析了NIST谱库中不包含的主要裂解产物可能的质谱裂解途径;可根据其中环己硫醇、邻苯二甲酰亚胺、二环己基二硫化物3个裂解产物共同判断防焦剂CTP的存在。     

裂解气相色谱/质谱联用研究防焦剂CTP的热裂解

正北京橡胶工业研究设计院采用裂解气相色谱/质谱联用法对防焦剂CTP的热裂解行为进行研究,并对部分热裂解产物的质谱碎裂机理进行探讨。结果表明:防焦剂CTP热裂解适宜条件为温度300℃,时间0.2 min,方式单纯瞬间裂解,固体样品直接进样;不同产地产品的裂解产物具有一致性,热稳定性好;裂解产物共10余个,主峰为原分子,次强峰为邻苯二甲酰亚胺。解析了NIST谱库中不包含的主要     

气相色谱/质谱联用鉴定胶料中防焦剂CTP的方法

根据防焦剂CTP与促进剂反应生成邻苯二甲酰亚胺的机理,建立气相色谱/质谱联用(GC/MS)鉴定混炼胶和硫化胶中防焦剂CTP的方法,并通过已知配方胶料验证。与红外光谱法鉴定硫化胶中防焦剂CTP相比,GC/MS法鉴定混炼胶和硫化胶中防焦剂CTP灵敏度和准确性较高,操作简单。     

橡胶防焦剂CTP的功用

本文主要介绍防焦剂CTP(N—环己基硫代邻苯二甲酰亚胺)的作用，研究其对胶料抗焦烧性能、混炼工艺和贮存稳定性的影响。研究结果表明．在硫黄硫化体系中加入少量防焦剂CTP，即可提高胶料的抗焦烧性能和贮存稳定性．可将二段混炼工艺改为一段混炼工艺，缩短了混炼时间，提高了劳动生产率；在用量相同的情况下．防焦剂CTP的防焦效果优于防焦剂PA和NDPA。     

利用防焦剂处理自硫氟橡胶

一、前言防焦剂是一种能防止胶料在加工期间产生早期硫化,而又不妨碍硫化温度下促进剂正常作用的助剂,已经广泛应用于橡胶工业。关于防焦剂对于不同硫化体系的作用,国内外进行了大量研究并提出了各种看法。防焦剂CTP(又名PVI)的化学名称为N-环己基硫代邻苯二甲酰亚胺,结构式为     

橡胶防焦剂CTP合成工艺及装置

由王传华申请的专利(公开号CN101624364,公开日期2010-01-13)橡胶防焦剂CTP合成工艺及装置,提供了一种橡胶防焦剂CTP合成工艺,即将环己基硫基氯与邻苯二甲酰亚胺钠盐连续加入到管式反应器中,通入氮气,使其在管式反应器中瞬间混合充分并发生缩合反     

焦烧时间对钢丝-天然橡胶黏合性能的影响

探究了N-环己基硫代邻苯二甲酰亚胺(防焦剂CTP)用量对胶料物理性能、交联密度和黏合性能的影响.结果表明,随着防焦剂CTP用量的增加,焦烧时间和工艺正硫化时间逐渐延长,未添加黏合组分的胶料的交联密度有所升高,添加黏合组分的胶料交联密度呈先升后降的趋势.CTP用量对胶料的力学性能没有明显的影响,而压缩生热和黏合性能都与C...     

6项橡胶行业新制修订国家标准批准实施

<正>2019年10月18日,国家市场监督管理总局、国家标准化管理委员会批准并公布了343项国家标准,其中《防焦剂N-环己基硫代邻苯二甲酰亚胺(CTP)》等6项与橡胶行业相关的新制修订国家标准(如表1所示)将于2020年实施。     

防焦剂—CTP通过技术鉴定

在橡胶加工过程中,由于机械生热和高温环境,使胶料容易过早地出现焦烧现象,从而造成浪费。因此,在工业生产中,常常加入防焦剂,用以提高胶料加工的安全性与贮存的稳定性。CTP(N-环己基硫代邻苯二甲酰亚胺)     

一锅法合成N-烯丙基邻苯二甲酰亚胺

以邻苯二甲酰亚胺和烯丙基氯为原料,采用一锅法合成,经红外和核磁氢谱表征,确定该产物为N-烯丙基邻苯二甲酰亚胺。考察原料配比、反应时间、反应温度、溶剂对产物收率的影响,得到优化反应条件:n(烯丙基氯)∶n(邻苯二甲酰亚胺)=1.5∶1,在60℃下反应12 h,N-烯丙基邻苯二甲酰亚胺的收率可高达88.5%。     

Solid‐phase microextraction (SPME) in polymer characterization—Long‐term properties and quality control of polymeric materials

Solid‐phase microextraction (SPME) in combination with GG‐MS was applied to quality control polyamide 6.6 collected for recycling and to study the long‐term properties and degradation of nitrile rubber, polyethylene, and polyamide 6.6. The migration of plasticizer and other additives reduces the service‐life and changes the properties of the material. It is also a possible health hazard, for example, legislation against the use of brominated flame retardants in plastic materials, is under discussion, and fast and reliable methods are required to detect such compounds in plastic materials collected for recycling. SPME rapidly and effectively extracted several brominated compounds from in‐plant collected polyamide 6.6. Migration of tris(2‐butoxyethyl)phosphate plasticizer and its degradation products from nitrile rubber during long‐term thermal ageing at 60 and 80°C was shown by SPME‐GC‐MS, while the plasticizer was not volatile enough to be detected by traditional HS‐GC‐MS. In accordance the number of degradation products extracted from thermo‐oxidized PE by HS‐SPME was three times larger than the number detected after HS‐GC‐MS analysis. SPME‐GC‐MS could also detect early signs of degradation in thermo‐oxidized virgin and in‐plant recycled polyamide 6.6 before any signs of degradation were observed by, for example, tensile testing or FTIR. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 867–873, 2003     

过氧化物预硫化与硫黄硫化制备的医用天然胶乳制品热氧稳定性的差异

用TG-DTG方法研究动态空气状态下过氧化物预硫化天然胶乳(PPVL)制品试样和硫黄硫化天然胶乳制品试样的热氧降解。结果表明，PPVL试样和硫黄硫化体系试样的热氧降解反应为二步反应，前者的热氧降解起始温度To，DTG主降解峰温度L，终止温度T1均明显低于后者，反应活化能也明显低于后者；在较低温度下，两者均出现增重过程，前者比后者较明显，是后者的4．7倍；DTA曲线显示，前者出现的放热效应初始温度比后者提前。     

不同种植年份橡胶树PR107生胶性能的研究

研究了1981年、1986年、1990年、1996年4种不同种植年份的PR107天然橡胶的生胶性能和混炼胶的硫化特性以及硫化胶的物理机械性能,并对胶样进行TG/DTG分析。结果表明:1986年份的生胶相对分子质量最大,硫化速率最快,硫化胶的物理机械性能最好,热稳定性最好;1996年份的生胶的热稳定性最差。     

Studies on Thermal Degradation of Cellulosic Fibers Treated with Flame Retardants

Hemp fabric, one of the most flammable materials, was treated with compounds containing different kinds of elements that contribute to flame retardation. For a study of flame retardation from the standpoint of thermal degradation, the samples were subjected to thermogravimetry (TG) and differential thermal analysis (DTA) in air from ambient temperature to 600℃. The apparent activation energy (Ea) is evaluated by Broido's method at different stages of thermal degradation to observe the variation of Ea in the process of thermal degradation. Flame retardation of samples was determined by limiting oxygen index (LOI) to find the effects of the different compounds on flammability and the thermal degradation of the hemp fabric. The composition of the chars was studied by the IR spectra to obtain information concerning the thermal degradation mechanism. Compared with flammable hemp, the hemp fabric treated with flame retardants showed a higher LOI but lower Ea and decomposition temperatures, which indicated that some compounds make the hemp fabric decompose at lower temperatures, resulting in less flammable products.     

Effect of γ-tocopherol on formation of nonvolatile lipid degradation products during frying of potato chips in triolein

Formation of undesirable odors and flavors during food processing operations is an important problem for the food industry. To determine the effect of γ-tocopherol on these negative attributes of fried food, we fried potato chips in triolein with 0, 100, or 400 ppm γ-tocopherol. Triolein extracted from potato chips was sampled for residual γ-tocopherol and nonvolatile degradation products after the chips were aged. RP-HPLC coupled to atmospheric pressure chemical ionization MS and size-exclusion chromatography was used to analyze, samples for degradation products in the triolein absorbed in potato chips as well as the fryer, triolein. MS results showed that γ-tocopherol reduced the production of nonvolatile degradation products in the triolein absorbed by the potato chips and in the triolein in the fryer. Fryer oil samples and extracted potato chip oils with 400 ppm γ-tocopherol had a significantly lower production of degradation compounds than did samples with 100 ppm γ-tocopherol. Both fryer oils and potato chips containing 100 ppm γ-tocopherol had significantly fewer nonvolatile degradation products than did the samples without γ-tocopherol. These nonvolatile compounds are known precursors of negative odors and flavor compounds produced during the frying and aging of foods.     

Thermal degradation of ethylene–carbon monoxide alternating copolymer under inert atmosphere

This work aims to understand the mechanism of the thermal degradation of the ethylene–carbon monoxide (E-CO) alternating copolymer under mild conditions. The copolymer was subjected to accelerated ageing in an oven at different temperatures below the copolymer melting point, under argon atmosphere, and in the absence of light. The properties of the aged samples were compared with the properties of the untreated copolymer. Untreated and aged samples were analysed by mass spectroscopy (MS) with the direct introduction probe (DIP) and pyrolysis (Py) techniques. The accelerated ageing experiments showed that the thermal degradation of the E-CO alternating copolymer under inert atmosphere is characterized by chain cross-linking, loss of water, and changes in the UV absorption spectrum. The IR spectrum shows modifications only for highly degraded samples in which O−H and C=C groups are present. The experiments performed with the DIP-MS technique have confirmed that the E-CO alternating copolymer loses water during its thermal ageing. The pyrolysis products of the copolymer are linear molecules with 1,4-diketonic structure, 2-cyclopentenone derivatives, alkyl furans, and aromatic compounds. These results suggest that during the thermal degradation of the E-CO alternating copolymer under inert atmosphere, and at low temperatures, aldol condensations and/or dehydration to furan rings probably occur. © 1998 SCI.     

Chemical analysis of environmental samples collected in Iraq: Analysis for the presence of chemical warfare agents

Nineteen samples from the United Nations Special Commission 65 on Iraq (UNSCOM 65) were analyzed for chemical warfare (CW) related compounds using a variety of spectroscopic and chromatographic techniques including multinuclear NMR, GC (phosphorus, sulfur and atomic emission detection), GC/MS (electron impact and chemical ionization), tandem MS, HPLC/ion chromatography, HPLC/thermospray/MS, FTIR, ICP and GFAA. The samples consisted of one piece of cloth, one piece of wood, six waters, six soils, two vegetation samples and two mortar shell crosscut sections. No intact CW agents were detected; however, diethyl phosphoric acid was unambiguously identified in three of the water samples and ethyl phosphoric acid was tentatively identified, at lower levels, in one of the water samples. Diethyl phosphoric acid and ethyl phosphoric acid are degradation products of munitions-grade Tabun (GA), an organophosphorus nerve agent. However, these compounds are also degradation products of the Chemical Weapons Convention (CWC) scheduled compound Amiton as well as many commercially available pesticides.     

Application of computed X-ray tomography scanning in the study of thermo-oxidative degradation of thick-walled filled natural rubber vulcanizates

The aging of five thick-walled natural rubber compounds has been studied by computed X-ray tomography scanning and crosslink density measurements. The compounds were compouded as ordinary carbon-black-filled rubbers with sulfur and peroxide as curing agents. The rubber samples were aged in air at 70, 100, and 150°C for 1000h. The relatively new technique of computed X-ray tomography scanning proved to be a good method for studying the aging procedure, and especially for following the crack propagation in the surface. Antioxidants (TMQ and 6PPD) had a low effect on the resistance toward oxidative degradation and crosslinking under these conditions. Surprisingly, the efficient sulfur-vul-canized material had a poor resistance toward thermal degradation. When the crosslink density and the computed X-ray tomography scanning results were compared, it was assumed that the computed X-ray tomograph detected oxygen in the surface, both as elementary oxygen and as oxygen in degradation products, i.e., in carbonyls. The results agree well with the theory that oxidative aging is limited by the ability of the oxygen to diffuse into the material.     

甜菜碱对异戊橡胶热降解性能的影响

采用热重分析法研究氮气气氛下甜菜碱对异戊橡胶(IR)热降解性能的影响。结果表明:添加甜菜碱不会改变IR的热降解机理;添加甜菜碱的IR胶料的起始降解温度、最大降解温度和反应活化能均比未添加甜菜碱的IR胶料高,表明甜菜碱提高了IR胶料的热稳定性。     

The effects of clay on the thermal degradation behavior of poly(styrene-co-acrylonitirile)

The thermal degradation of poly(acrylonitrile-co-styrene) (SAN) and its clay nanocomposites were studied using TGA/FTIR and GC/MS. Virgin SAN degrades by chain scission followed by β-scission, producing monomers, dimers and trimers. The degradation pathway of SAN in clay nanocomposites contains additional steps; extensive random chain scission, evolving additional compounds having an odd number of carbons in the chain backbones, and radical recombination, producing head-to-head structures. Since acrylonitrile-butadiene-styrene copolymer (ABS) has butadiene rubber incorporated as a grafted phase in a SAN matrix, ABS follows a similar degradation pathway as that of SAN. The effect of butadiene rubber is similar to that of clay, leading to extensive random scission and an increase in thermal stability, but as not effective as clay due to its shorter duration. Eventually, the butadiene rubber phase degrades to small aliphatic molecules.