Analysis of Pyrolysates for Polysulphoneamide Fiber by Py-GC/MS

Pyrolysis of polysulphoneamide fiber has been investigated using pyrolysis gas chromatography-mass spectroscopy at the different temperatures from 420℃ to 750℃. Its compositions of pyrolysates have been analyzed. At 420℃,pyrolysis of molecular chain could not completdy take place, 12 compounds of pyrolysis have only been identified. When the temperature increases, the compositions of pyrolysate increase sharply. Several compounds, especially sulfur dioxide, benzene, aniline, benzoic acid, 1,4-benzene dicaronitrile, N-phenyl-acetamide, diphenylamine, benzc[g] isoquinoline, N-phenyl-benzamide, hi-（ 4-cyanophenyl ）benzamide, could be formed. The degradation mechanisms which are determined by structure and amount of the thermal decomposition products are described. During pyrolysis, for polysulphoneamide, polymeric chain scissions take place as a successive removal of the monomer units from the polymeric chain. The chain scissions are followed by secondary reactions, which lead to a variety of compounds. Additional reactions can also take place during pyrolysis.     

Analysis of Pyrolysates for Phenol Formaldehyde Resin by Py-GC/MS

Pyrolysis of phenol formaldehyde resin has been investigated by Pyrolysis Gas Chromatography-Mass Spectroscopy at the different temperatures from 500℃ to 750℃. Its composition of pyrclysates has been analyzed. Several compounds, especially benzene, toluene, p-xylene could only be formed above 500-550℃. Howerver, peak intensities for some pbend derivatives were decreased at the higher temperature. During pyrolysis, for thermo-setting phenol formaldehyde resins, polymeric chain scissions take place as a successive removal of the monomer units from the polymeric chain. The chain scissions are followed by secondary reactions, which leads to a variety of compounds. Addition reactions can also take place among the double-bond compounds during pyrolysis.     

Pyrolysis Process in Aramid Fibers Investigated by Py-GC/MS ＆ TGADTA/MS

Poly （ m-phenylene isophthalamine） （PMIA） and Poly（ p-phenylene terphthalamine） （PPTA） are among the most important high-temperature resistant aramid fibers. The pyrolysis behaviors of these two fibers under inert gases were studied using pyrolysis-gas chromatography/mass spectrometry （Py-GC/MS） and thermogravimetric analysis coupled with mass spectrometry （ TGA-DTA/MS ）. The pyrolysis processes of PMIA and PPTA are distinguishing, and the stepwise pyrolysates reflect these differences. A mechanism system of pyrolysis is suggested, which involving hydrolysis and homolysis, At low pyrolysis temperatures, hydrolysis is a primary reaction, and it is very noticeable in the first-step pyrolysis region of PMIA. Elevating pyrolysis temperature, homolysis is enhanced and keep a large advantage in the high temperature range. On the other hand, at higher temperatures, carbonization happens and the homolysis and carbonization of PPTA are emphasized more than of PMIA.     

Synthesis of novel active ester ether resin and its effects on positive thermal CTP plates

A novel active ester ether resin, consisting of p-hydroxyphenylacetic acid and a mixed-phenol novolac resin, was produced by the addition of ethyl vinyl ether to a carbonyl novolac resin. This study investigated the conditions of its synthesis and characterized its structure using infrared and 1 H NMR spectroscopies, and gel-permeation chromatography. Its solubility in alkaline solution differed greatly before and after decomposition. The results of thermal gravimetric analysis confirmed the formation of an active ester ether resin of p-hydroxyphenylacetic acid and novolac resin. The resin had acidolysis activity at room temperature and pyrolysis activity at high temperatures (140-200°C) and could be used in the imaging layer of a positive thermal plate for computer-to-plate processes as an inhibitor/accelerator to improve its alcohol resistance, alkali resistance, sensitivity, lattice point reducibility, and developing tolerance.     

Preparation and Properties of Polylactic Acid (PLA)/Nano-SiO2 Composite Master Batch with Good Thermal Properties

In order to improve the thermal properties of polylactic acid( PLA) master batch,the nano-SiO2 was applied to mixing with PLA. The structure and thermal properties of the composite master batches were studied. The results showed that the nano-SiO2 modified by 3% coupling agent KH-570 could be dispersed evenly in PLA in small scale. The thermal decomposition temperature of composite master batches increased by 6. 20-10. 80 ℃, the glass transition temperature increased by 0. 22-5. 16 ℃,and the heat enthalpy at the glass transition temperature increased by 0. 574-2. 437 J /g,compared with pure PLA. The composite master batch possessed superior thermal stability and heat resistance.     

Study on the Model of Thermal Channel Spinning Process for PET Polymer

A mathematical model to describe the TCS process inPET high-speed melt-spinning is established.The de-velopment of crystallinity,molecular orientation andmorphological features of high-speed-spun PET fiberin TCS process is investigated at take-up speeds rangingfrom 3600-4400 m/min and thermal channel tempera-tures ranging from 160-200℃ by simulation.The pro-files of tensile force,running velocity,temperature,bi-refringence,crystallinity and diameter in the TCS spin-line for various process conditions are obtained.Thepredicted results using this model are compared with themeasured crystallinty,diameter and birefringence.Theresults indicate that they are in fairly good agreement.The"necking point"in the TCS spinline can be predictedby this model,and its position changes with the corre-sponding process parameters such as take-up speed andthermal channel temperature.It is found that the neck-ing point moves towards the spinneret when the take-upspeed or the thermal channel temperature increases.     

DSC Study of Thermal Properties of Biodegradable Poly （Butylene Succinate-co-terephthalate）

Poly （ butylene succinate ） （ PBS ）, poly （ butylene terephthalate） （PBT） and poly （butylene succirmte-coterephthalate） （PBST）s were synthesized from dimethyl succinate and/or dimethyl terephthalate reacting with 1,4- butanediol through a process of transesterification/ polycondmsation in the presence of a high effective catalyst and characterized by means of GPC and DSC. The investigation was mainly focused on the influence of content of terephthalate units on the molecular weight and thermal properties of resulting polymers. It is revealed that the melting temperature and crystallinity of synthesized polymers decrease first with the increase of terephthalate units, then shift to rise gradually by DSC measurements. The results of Flory equation suggest sequence structure of PBSTs is random.     

A research on high-temperature permittivity and loss tangent of low-loss dielectric by resonant-cavity technique

Resonant-cavity technique was introduced to measure the permittivity and loss tangent of low-loss dielectrics. The dielectric properties at 9-10 GHz are measured accurately at the temperature up to 800 ℃ by the resonant cavity technique. The only electrical parameters that need to be measured are quality factors （Q） and resonant length （L） of resonant cavity loaded and unloaded with dielectric sample. Moreover, the error caused by thermal expansion effect was resolved by error analysis and experimental calibration.     

INFLUENCE OF POLYMER CHARACTERISTICS AND MELT-SPINNING CONDITIONS ON THE PRODUCTION OF HIGH RANDOMNESS 60PHB/PET THERMOTROPIC LIQUID CRYSTAL COPOLYESTER FIBER

Six samples of linear high randomness 60PHB/ PET thermotropic liquid crystal copolyesters are made by melt copolymerization at 290℃ , whose randomness about 0.955 is measured by the discernible 'H-NMR spectrometer. High tenacity, high module fiber is prepared by melt spinning in liquid crystal phase. The effect of molecular weight, shear rate, temperature as well as spinning drawn ratio on the mechanical behavior of 60PHB / PET copolyester fiber are shown that, lower shear rate (2~ 10 s~(-1)), higher temperature melting (300℃ ), lower temperature spinning (280℃ ) and higher molecular weight are favourable to the increase of the fiber mechanical properties. With the variance of drawn ratio, fiber mechanical property has a transition point due to traversion from shear-orientation to drawn-orientation. The copolyester fiber has high crystallinity, high orientation at the crystalline region, high chain orientation and high regular fibrillar structure.     

Efficient Method to Achieve Enhanced Thermal Dimensional Stability and Desired Dimensions of Hollow Polyester Fiber

This study has developed an efficient method to achieve excellent thermal dimensional stability and desired dimensions of hollow polyester fiber. Firstly,the influence of thermal treatment temperate( 140-180 ℃) on the degree of shrinkage of fiber was investigated. The influence was also analyzed with a 2nd heating to simulate the application situation. It was discovered that the heat treatment at a temperature which was above the application temperature( 2nd heating) would efficiently remove the internal stress in the fiber and improve the thermal dimensional stability.Secondly,the impact of heat treatment temperature on the fiber diameter and the degree of hollowness were studied. The results implied that with a fixed fiber length, higher treatment temperature led to thinner fiber and a lower degree of hollowness.Last but not least,key parameters that could further influence the fiber dimensions were investigated. The results suggested that the fiber diameters and the degree of hollowness could be further controlled by tuning the drawing speed,the spinning meter pump output and cooling status while the spinneret parameters were fixed.     

β-紫罗兰酮热裂解行为的初步探讨

采用在线热裂解-气相色谱/质谱(Py-GC/MS)联用技术研究了在氦气氛围中β-紫罗兰酮在300、400、500、600、700、800℃下的热裂解行为,结果表明:①β-紫罗兰酮可以裂解生成48种物质;②在600℃以下只有10.765%的β-紫罗兰酮发生裂解;在700、800℃裂解加剧,有18.149%和21.286%的β-紫罗兰酮发生裂解;③同时随着裂解温度的升高,形成的危害性芳香烃类化合物的相对含量也逐渐增大。此外,根据主要裂解产物对β-紫罗兰酮的裂解机理进行了初步探讨。     

松木屑非等温热解动力学研究

通过热重分析法在不同升温速率(分别为10,30,50℃.min-1)下,采用非恒温热重法,以氩气为载气,流速60 mL.min-1,初温为30℃,加热终温为950℃.对粒径为80目的松木屑热裂解时的热失重行为进行了研究.结果表明:松木屑热解分为四个阶段,主要由预热干燥阶段、热解预热阶段、热分解阶段和热缩聚阶段4个阶段组成;生物质松木屑主反应阶段主要集中在180～600℃左右;随着升温速率的增大,松木屑原料热解的起始温度、热解最大速率所在的温度Tmax及热解终止温度都向高温处稍微移动.使用了Flynn-Wall-Ozawa积分法、Coats-Redfern积分法和Achar微分法对松木屑热解动力学参数进行求取,Flynn-Wall-Ozawa积分法得到的松木屑在热解过程中不同失重率下(0.1～0.80)的活化能都集中在142.35～220.12 kJ.mol-1范围内.按照Bagchi法对松木屑热裂解过程的最概然机理函数进行了推断.松木屑热裂解的最概然机理函数为15号机理函数随机成核和随后生长,反应级数n=2(Code:AE2),函数名称是Avrami-Erofeev方程.     

玉米秸秆颗粒燃料热解气化试验研究

以玉米秸秆颗粒燃料为原料,研究了生物质空气热解气化(下吸式固定床气化炉)、富氧热解气化(鼓泡式流化床气化炉)和无氧热解气化(慢速连续热解气化炉)的热解气化特性.三种热解气化装置并联,共用一个控制系统,产生的生物质燃气经过冷凝器等后进入储气柜.燃气成分由气相色谱分析,成型颗粒、颗粒炭、生物油热值采用快速量热仪测量分析.结果显示,空气热解气化在热解温度为660~670℃时燃气低热值最高,约为3.91~4.44MJ/Nm3;富氧热解气化燃气低热值最高可达8.48~9.38MJ/Nm3(热解气化温度为575~750℃时);无氧热解气化在热解温度为380~530℃时的燃气低热值约为14.51~16.49MJ/Nm3,并可联产生物炭、生物油等.     

退役硅橡胶复合绝缘子热降解行为的研究

采用在线热裂解-气质联用（Py-GC-MS）技术对废旧硅橡胶复合绝缘子在不同温度下（300 ℃,400 ℃,500 ℃,600 ℃）的热降解行为进行了研究,并通过质谱中裂解产物的碎片离子信息对其裂解机理进行探究。结果表明：硅橡胶裂解产物为一系列二甲基硅氧烷环体及少量的链状硅氧烷,主要环体为六甲基环三硅氧烷（D₃）、八甲基环四硅氧烷（D₄）及环五硅氧烷直至环九硅氧烷;较高的裂解温度下,大环基本裂解完全,仅剩小环裂解产物。因此用热裂解处理废旧硅橡胶时,温度需要达到500 ℃及以上才会有较好的效果。     

裂解气相色谱质谱法研究废旧ABS塑料的热降解行为

采用裂解气相色谱质谱联用技术对ABS塑料的热降解行为进行了研究.在氦气氛围中,500℃下对ABS进行热裂解,通过色谱质谱联用仪对裂解产物进行了定性分析,共鉴定出苯乙烯、甲苯和4-苯基丁腈等31种裂解产物.根据裂解产物信息和有机物热裂解反应的原理对ABS的热裂解反应机理作了探讨.ABS塑料的热降解过程是典型的自由基历程,解释了裂解产物中芳香烃类化合物、脂肪烃类化合物、腈类化合物和含溴酚类化合物的生成机理.ABS的高温降解过程不是三种结构单元降解过程的简单累加,三种结构单元在其降解过程中相互明显影响,最终导致裂解产物在结构和类别上的多样性.废旧塑料ABS热裂解过程会产生多种有害污染物,因此,选择合适的裂解工艺条件,既可得到更多有用的裂解产物,又可减少对环境的污染.     

喷雾热解法制备Al_2O_3粉末

以AlCl3.6H2O为原料,采用喷雾热解法制备了纯度较高的Al2O3粉末,并利用XRD,SEM技术和比表面积分析仪研究了Al2O3粉末的物相组成、微观形貌及比表面积.热力学计算和DSC-TGA分析分别表明:在800~2 200 K温度范围内,热解主反应可以发生,提高温度更有利于反应发生;氯化铝热解适宜的温度为800℃.实验结果表明:喷雾热解最优条件是热解温度为750~850℃,AlCl3溶液质量分数为15%,热解时间为20 min.热解产物Al2O3粉末满足电解铝要求.     

天津市政污泥热解及燃烧动力学特性的分析

利用热重分析仪,在氮气和空气气氛下分别对天津市政污泥进行热分析实验,并采用热重、微分热重、差示扫描量热等方法分析了市政污泥的热解特性及燃烧特性.实验结果表明城市污泥燃烧热反应可分为4个阶段:水分蒸发析出、污泥有机挥发成分析出燃烧、污泥有机质及固定碳燃烧、燃烧残余物及难分解物的分解.在实验条件下,污泥样品着火温度为277.5,℃,燃尽温度为540,℃.建立了天津市政污泥燃烧动力学模型,采用连续两方程拟合的方式,得到了上述主要阶段的表观活化能Ea和指前因子A.     

氯化钠改性煤热解脱硫技术的试验研究

采用固定床反应系统对合山煤进行热解挥发分损失和脱硫效果的试验研究.研究热解温度、热解时间、不同添加剂对煤中挥发分和硫含量变化的影响.由试验结果可知,对于劣质合山煤添加氯化钠,在400℃的空气气氛下,经过10 min的热解,硫的含量可以降低到2.010 2%.