橡胶籽壳/苯酚液化物酚醛树脂的合成及表征

采用液化技术和树脂化技术,制备了橡胶籽壳/苯酚液化物(简称液化物);然后以此为原料,制备了胶合板用液化物PF(酚醛树脂)胶粘剂,并采用单因素试验法和正交试验法优选出制备液化物PF的最佳工艺条件。研究结果表明:当反应温度为90℃、n(甲醛)∶n(液化物)=2.0∶1.0、反应时间为2.0 h和n(氢氧化钠):n(液化物)=0.7∶1.0时,由液化物PF胶粘剂压制而成的胶合板,其湿态胶接强度(为1.36 MPa)相对最大,并且达到GB/T 9846—2004标准中I类胶合板的指标要求;液化物PF与纯PF的结构基本相似,但前者的固化温度略高于后者、热稳定性低于后者。     

基于TGA-FTIR和无模式函数积分法的稻壳热解机理研究

利用热重红外联用技术(TGA-FTIR)和无模式函数积分法,研究了不同升温速率(5、10、20、30 ℃/min)下,稻壳的热解特性和热解动力学,深入探讨其热解机理。TG和DTG研究表明,稻壳的热解过程分为干燥、快速热解和炭化3个阶段,随着升温速率的增加,TG和DTG曲线向高温一侧移动。稻壳热解气体成分含量最多的是CO₂,醛、酮、酸类以及烷烃、醇类和酚类等有机物。通过无模式函数积分法:FWO法和KAS法,计算得到的活化能随着转化率(α)增加数值波动明显,证明稻壳热解过程发生复杂的重叠、平行和连续的化学反应。0.1≤α<0.35,半纤维素的支链首先降解,然后是主链降解。0.35≤α≤0.7,纤维素首先转化为中间产物活性纤维素,然后活性纤维素再次降解。0.7<α≤ 0.8,主要是木质素降解,生物质中可降解的挥发分减少以及低反应活性的焦炭的不断生成是造成此阶段活化能快速增加的主要原因。总之,生物质三组分化学成分和结构差异造成不同转化率下活化能的差异。     

板栗壳的热解特性研究

采用热重分析仪和三种动力学计算方法研究了板栗壳的热解过程,可分为失水干燥、主热解和炭化三个阶段。含量较高挥发分(68.42%)造成主热解区间质量损失最多,主要是木质素、纤维素和半纤维素三种生物质组分的分解,其含量和特性使热解过程产生不同趋势。提高升温速率产生的热滞后现象使热解不够充分,导致主热解阶段活化能和频率因子增大。     

橡胶籽壳制活性炭的研究

本文研究了橡胶籽壳用氯化锌法制活性炭的可能性,探索了最佳工艺条件,结果表明在500℃下灼烧3h,锌渣比为2.0～2.2:1时,所烧得的活性炭亚甲蓝脱色力可达15ml。     

模式拟合法和无模式函数法对月桂酸热解行为及机理的研究

通过综合热分析实验研究了月桂酸粉体在氮气及空气气氛下的热解动力学行为.实验结果表明,氮气气氛中30μm月桂酸粉体快速热解气化,无燃烧放热反应.而不同升温速率条件下,空气气氛中月桂酸粉体的热解包括快速热解氧化及残余物质缓慢热解氧化两个阶段.运用模式拟合法(Coats-Redfern法)求解氮气与空气气氛中月桂酸主要热解阶...     

木材苯酚液化物碳纤维原丝的热力学性能研究

以木材苯酚液化物为原料,加入六次甲基四胺熔融纺丝后,经甲醛和盐酸溶液固化处理后得到木材液化物碳纤维原丝。利用热重分析法对原丝的热解过程及其动力学规律进行了研究。研究结果表明,原丝的最大热解速率出现在510℃,并且在748℃出现了二次热失重,最终热失重较少,热稳定性较好。在0～600℃之间木材液化物纤维存在两个明显的放热峰,且随着升温速率的增加,其放热峰向高温方向移动,放热峰的峰形也加宽变大。两个放热峰的表观活化能分别为69.36和59.02 kJ/mol;反应级数分别为0.862和0.734,且都小于1,说明两次分解反应比较复杂。     

生物质壳类物热解动力学研究

利用热重分析研究不同升温速率下3种生物质(核桃壳、花生壳和葵花籽壳)的热失重行为,采用Coats-Redfern法计算得到了3种生物质在不同升温速率、不同气氛下反应动力学参数。结果表明,3种生物质在热解主要阶段可由一级反应过程描述。     

基于热重-红外联用技术分析油酸的热解特性及动力学分析

利用热重红外联动技术（TG-DTG-FTIR）研究了橡胶籽油中的单不饱和游离脂肪酸油酸组分在不同升温速率（5℃/min、10℃/min、20℃/min、30℃/min）下的热解特性。然后,用多元线性回归法对油酸非等温热解所得到的特性参数进行研究并计算,求得不同升温速率下对应的反应级数、活化能和指前因子,并对不同升温速率下油酸热解反应活化能和指数前因子作线性拟合。结果表明：油酸热解过程主要可分为0～268℃和268～300℃两个阶段,由红外谱图特征峰的分析可知,不同升温速率下,在油酸热解的阶段内均出现了水蒸气、CH₄、CO₂和CO这4种主要气体挥发分。随着升温速率的增大,油酸热解的最大失重速率随之增大,热解区间也向着高温段移动,同时计算在升温速率从5～30℃/min的过程中,反应级数n=1时,热解反应活化能由105.57kJ/mol降低至93.99kJ/mol,指数前因子由6.99×10⁶降低至6.7×10⁵;n≠1时,热解反应活化能由102.45kJ/mol降低至93.38kJ/mol,指数前因子由3.13×10⁶降低至2.97×10⁴,反应活化能和指数前因子随升温速率的增大出现明显减小。通过对不同升温速率下油酸热解反应的活化能和指数前因子进行线性拟合后发现,两者间具有较好的补偿效应。     

小桐子壳热解及其挥发性产物特性分析

选用小桐子壳作为原料,采用热重-红外联用(TG-FTIR)和热裂解-气相色谱质谱联用(Py-GC/MS)技术,研究小桐子壳的热解特性以及300~800℃热解过程中产物的组分信息和有机化合物中官能团随温度的变化情况,同时利用Coast-Redfern积分法求解不同升温速率下的动力学参数。结果表明,小桐子壳的热解过程分为干燥(30~100℃)、预热解(100~258℃)、热解(258~420℃)和炭化(420~900℃)四个阶段。随升温速率升高,小桐子壳的最大质量损失率依次增加,升温速率的升高对小桐子壳热分解速率具有促进作用。随热解温度升高,吸收峰处存在明显的强度变化,CO2、醛酮类等化合物的吸收峰强度逐渐降低甚至消失;小桐子壳热解过程中的气体产物成分主要为CO, CO2, H2O等,主要挥发性有机产物为苯酚、羰基化合物、愈创木酚类等,热解温度由400℃升至700℃时,酚类化合物的峰面积比例从35.94%升至59.59%、羰基化合物的峰面积比例从36.90%降到11.87%。小桐子壳热解动力学参数n=1时,其反应表观活化能最大为61.34 kJ/mol,且三个升温速率的拟合相关系数均在98%以上。小桐子壳热解动力学参数n≠1时,选取相关系数最大时的n值为反应级数,则n=0.2,反应活化能E为47.64 kJ/mol,指数前因子A为0.83。随升温速率的升高表观活化能依次递减,且拟合相关系数均在97%以上。     

葵花杆的热解特性及热解产物分析

为充分利用生物质葵花杆,采用同步热分析仪以升温速率为影响因素对葵花杆的热解特性进行研究,利用Coats-Redfern积分法计算主要阶段热解动力学参数,并采用气相色谱/质谱联用仪对热解产物进行了定量分析.研究结果表明:葵花杆的热解过程可分为预热干燥、主要热解及炭化3个阶段;随着升温速率的增大,葵花杆热解的TG曲线向高温...     

Optimization of rubber seed oil extraction using liquefied dimethyl ether

The objective of this study was to find the optimal condition for the extraction of rubber seed oil (RSO), using liquefied dimethyl ether (DME). Response surface methodology with a spherical central composite design model was employed to determine the optimal extraction condition, consisting of a seed moisture content (%wt), a solvent to solid ratio (g/g), and an extraction temperature (°C). A quadratic regression equation suggested the optimal extraction condition was a moisture content of 56.4%wt, a solvent to solid ratio of 6.7 (g/g), and a temperature of 33.3?°C. At this condition, the RSO yield predicted by the model gave a slight deviation of 0.68% from the experimentally validated results (41.48 versus 41.20%). RSO has a kinematic viscosity of 36.8 cSt, an acid value of 10.7 KOH/g oil, a fatty acid content of 5.1% and an unsaturated fatty acid content of 80%, resulting in the potential production of biodiesel, biolubricants, and biodegradable plastics.     

核桃壳液化及其与甲醛反应能力的研究

探讨了核桃壳在120℃、苯酚与核桃壳粉质量比为3/1和催化剂(浓硫酸,用量为苯酚的3%)存在下液化,通过分析液化体系内游离苯酚和残渣含量以及液化体系与甲醛反应能力发现,核桃壳的酚解和酚化反应主要发生在反应初期,以后逐渐减弱;液化体系内总的活性量由2部分组成,一是液化体系内游离苯酚贡献的活性量,二是体系内液化产物贡献的活性量。随着反应的进行,游离苯酚折算的耗醛量逐渐减少,液化产物的耗醛量逐渐增加,而总的液化体系中消耗甲醛的能力在逐渐减弱。     

基于无模式法推断石灰石分解机理新方法

提出一种基于无模式法推断反应机理函数的新方法。首先分析反应发生的过程,对机理函数作初步筛选;然后采用Popescu法通过函数拟合的线性相关度对机理函数作进一步的推断;最后采用单个扫描速率的微分法与等转化率法相结合的方法,以活化能为判据确定最概然机理函数。此方法可以从根本上消除动力学补偿效应的影响,而且计算过程中几乎没有作任何假设和近似处理,多重扫描速率法也可以减小微分计算所带来的误差。以活化能作为反应机理最终的判据,可以对机理函数进行明显的区分,避免了仅依赖函数拟合线性的微小差别进行判断的问题。因此,此方法得到的结果是可靠的。采用热重分析技术对3种石灰石分解反应进行研究,结果表明相界面反应控制的收缩圆柱体模型是石灰石分解的最概然机理函数,进一步证明了此方法的可行性。     

轮胎挤出生产线用自动递头装置设计

介绍轮胎挤出生产线用自动递头装置的设计。自动递头装置由外弧形辊道、内弧形辊道以及检测制品到达预定位置的来料检测装置组成,内、外两组弧形辊道均由气缸控制,外侧辊道带动力,内侧辊道为自由辊道,制品在两侧辊道中间通过;通过接近开关检测来料信号。自动递头装置可以实现自动将制品由下至上传送,无需人工干涉,提高生产连续性和生产效率。     

Pyrolysis kinetics and product properties of softwoods,hardwoods, and the nut shell of softwood

The pyrolysis of softwoods (Pinus (P.) densiflora, P. koraiensis), hardwoods (Quercus acutissima and Liriodendron tulipifera) and nut shell of P. koraiensis was investigated using a thermogravimetric analyzer and fixed bed reactor. Thermogravimetric analysis showed that the maximum decomposition temperature of each biomass was influenced by the ash content and lignocellulosic composition of biomass. The activation energy values also varied according to the content of hemicellulose and lignin of each biomass. Large amounts of acids, such as acetic acid, were recovered from the hardwood pyrolysis reaction due to their high hemicellulose content. The nut shell of P. koraiensis and softwoods with a higher lignin content produced higher yields of phenolic compounds than the hardwoods.     

Effect of auxiliary blowing agents on properties of rigid polyurethane foams based on liquefied products from peanut shell

The bio‐based rigid polyurethane (PU) foams were successfully prepared based on liquefied products from peanut shell with water as the blowing agent. The influence of reaction parameters on properties of rigid PU foams was investigated. Rigid PU foams showed excellent compressive strength and low shrinkage ratio, whereas their open‐cell ratio and water absorption were higher. Therefore, rigid PU foams were synthesized with petroleum ether, diethyl ether, and acetone as auxiliary blowing agents and their inner temperature, shrinkage performance, density, compressive strength, water absorption, and open‐cell ratio were determined. The results indicated that above rigid PU foams showed lower compressive strength than the original foam but their water absorption and close‐cell ratio were improved. Compared with the original foam, the highest inner temperature of rigid PU foams with petroleum ether, diethyl ether, and acetone as auxiliary blowing agents was reduced by 11, 19, and 23 °C, respectively. Typically, foams with petroleum ether as auxiliary blowing agent displayed better water absorption and swelling ratio in water and exhibited obvious improvement in close‐cell ratio. These foams were preferable for application in thermal insulation materials because of low thermal conductivity and better corrosion resistance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45582.     

Synthesis,characteristic, and properties of waterborne polyurethane based on natural rubber

A series of new waterborne polyurethanes (WPUs) was successfully prepared by prepolymer process from renewable source, hydroxytelechelic natural rubber (HTNR), with different amounts of DMPA (1.6–8.4 wt %), different molecular weights (1000–4000 g mol^?1), and different levels of epoxide (0%–20%) of HTNR. It was found that the urethane conversions of prepolymer were over 80% as calculated by FTIR technique. The resulting HTNR2000‐based WPUs exhibit a uniform particle size, which decreases from 420‐ to 83‐nm diameters with an increase in the amount of DMPA from 2.9 to 6.6 wt %. The particle size also decreases with an increase of soft segment or with an increase of epoxide content. They are well stable more over 6 months and without a significant difference in particle size compared with starting of them. Chemical structure of WPU films was confirmed by FTIR, ¹H‐NMR, and ¹³C‐NMR. Molecular weight and polydispersity were determined by SEC. In addition, thermal and water uptake properties were investigated. The experimental results reveal that the DMPA content, molecular weight of HTNR, and epoxide content play an important key role in water uptake and thermal properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

液化反应条件对核桃壳液化产物成胶特性的影响

研究了液化反应条件(苯酚/核桃壳质量比、催化剂浓硫酸用量、温度和时间)对核桃壳液化产物成胶特性的影响.研究结果表明,随着苯酚/核桃壳质量比的增大,液化残渣率下降,液化产物的耗醛量逐渐上升;随着催化剂浓硫酸用量、液化反应温度和液化反应时间的增加,液化产物的游离酚含量、可被溴化物含量及液化残渣率下降较快,但耗醛量下降缓慢或变化不大;相同液化反应条件下,液化产物的可被溴化物含量总比相应的游离酚含量高;在苯酚与核桃壳质量比3:1、催化剂浓硫酸用量3%、液化反应温度120℃、液化反应时间30min条件下获得的液化产物具有较好的成胶能力.     

基于相关积分优化方法的裂解炉优化

裂解炉是石油化工产业中重要设备,优化裂解炉运行状态对提升乙烯装置绩效至关重要。由于裂解反应机理复杂,裂解炉模型难以确定且扰动频繁,运用传统优化方法难以解决裂解炉运行优化问题。提出将相关积分优化方法应用于裂解炉运行优化,以解决裂解炉优化需要裂解炉具体模型、传统优化方法的自适应性与抗干扰性不满足裂解炉优化需求的两大问题。首先,分析影响裂解炉运行的主要操作参数,选取合适的操作变量,并构建优化目标函数;然后,采集操作变量与优化目标函数数据,建立裂解炉历史数据库。最后,基于相关积分优化方法,利用历史数据进行迭代计算以对裂解炉进行优化。仿真结果验证了相关积分优化方法在裂解炉优化中的有效性。