蜂蜜的热裂解产物分析

为了研究卷烟添加剂蜂蜜的热裂解产物对卷烟烟气成分的影响,应用热裂解-气相色谱/质谱（Py-GC/MS）联用技术,模拟卷烟燃烧的环境,对蜂蜜在不同裂解温度（300℃、600℃、900℃）和不同氧气浓度（大气环境、10%O2）下的裂解产物进行成分分析。结果表明,在相同裂解氛围和不同裂解温度中,高温时蜂蜜的裂解产物种类多于低温时的;在相同裂解温度和不同裂解氛围中,蜂蜜裂解产物的质量分数不同;蜂蜜在各种不同裂解条件下的主要产物是糠醛、5-甲基糠醛及5-羟甲基糠醛等醛类物质,还产生多种酮类和呋喃类等物质;蜂蜜的大部分热裂解产物是构成卷烟烟气香味的重要成分。     

杭白菊浸膏热裂解产物的GC/MS分析

用热失重(TG)技术以及在线热裂解(Py)技术对杭白菊浸膏热裂解产物进行了研究。TG曲线显示主要失重区间在120~620℃,质量损失高达87%,选取了失重比较大的几个温度点(300、400、550、620℃)和800℃作为裂解温度,以气相色谱-质谱法(GC/MS)分析其在不同温度下的裂解产物,并对添加不同量杭白菊浸膏的中试卷烟进行了评吸。结果表明:300、400、550、620、800℃裂解温度下检测到的挥发性热裂解产物分别为20种、29种、28种、26种,21种;550℃下杭白菊裂解产物主要是醛类、酮类、酯类和呋喃类物质;550℃时开始出现有害物质,且有害物质的量随着温度的升高而提高;杭白菊浸膏能够显著改善卷烟抽吸品质,赋予卷烟一种特殊的自然风味。     

香紫苏内酯的热裂解产物分析研究

为研究香紫苏内酯的高温裂解产物及其对卷烟抽吸品质的影响,在不同裂解氛围(空气和氮气中)和不同裂解温度(300℃、600℃和900℃)下,分别对香紫苏内酯进行热裂解。所产生热裂解产物用固相微萃取进行顶空吸附,并用气相色谱质谱联用仪进行分离和鉴定。结果表明,香紫苏内酯在不同裂解条件下的主要裂解产物是芳香族化合物、烯烃类、醛类、酯类、酮类、酚类和醚类等,这些裂解产物随裂解温度和裂解氛围的不同,其含量和种类有所差异。在相同的裂解氛围中随着裂解温度的升高,香紫苏内酯的裂解产物种类增加,含量也有所不同,说明裂解温度对裂解产物种类和含量影响很大;在300℃时,香紫苏内酯在空气氛围中和氮气氛围中分别生成20个和15个成分,在空气氛围下生成的3-甲基-2-丁烯醛、己醛、苯甲醛、辛醛、3-苯基-2-丙烯醛等物质,但在氮气氛围条件下没有生成。在不同热裂解条件下,香紫苏内酯热裂解均产生了香叶基丙酮和降龙涎香醚等香味成分,它们可提升卷烟烟气的香味品质。     

烟草植醇热裂解产物研究

为了研究植醇热裂解产物对卷烟品质的影响,利用热裂解-气相色谱/质谱法模拟植醇在卷烟燃吸过程中产物的变化情况;研究了在不同气体氛围(N2氛围,含10%O2的N2氛围)和不同裂解温度(300℃,600℃,900℃)条件下,植醇的裂解产物和对卷烟品质的影响,并对机理进行了初步的探讨。结果表明,植醇的主要裂解产物是新植二烯等烯烃类化合物,同时还生成了醇类、醛类、酮类、芳香烃等化合物,这些物质随裂解温度和气体氛围的不同其含量有所差异。     

PY-GC/MS技术研究烟草中苹果酸和柠檬酸的热裂解产物

研究苹果酸和柠檬酸热裂解产物对卷烟品质的影响。利用热裂解-气相色谱/质谱法模拟苹果酸和柠檬酸在卷烟燃吸过程中产物的变化,研究不同裂解温度(300℃,600℃,900℃)条件下苹果酸和柠檬酸的裂解产物和对卷烟品质的影响,并对机理进行了初步的探讨。在不同温度热裂解时,苹果酸的热裂解产物,主要是乙酸,丙烯酸和2,5-呋喃二酮,柠檬酸热裂解产物主要是丙酮和柠康酸酐。苹果酸和柠檬酸的热裂解产物都产生了大量的酸性物质。相比柠檬酸,苹果酸更利于改善吸味,平衡烟气,增加烟气浓度。根据苹果酸和柠檬酸裂解生成的主要产物,对裂解原理进行了探讨,认为苹果酸可能按照三种途径发生裂解,柠檬酸可能按照两种途径发生裂解。     

气相色谱-质谱法研究聚氯乙烯的热裂解行为

采用气相色谱-质谱法并结合热重分析法对聚氯乙烯(PVC)的热裂解行为进行了研究。首先对PVC的热失重行为进行考察,确定最佳裂解温度;然后分别在350℃和600℃下对PVC进行热裂解,并用气相色谱-质谱联用仪对裂解产物进行定性和半定量分析。结果表明:在350℃下,PVC裂解产物主要以HCl和苯等易挥发物质为主;在600℃下,裂解产物为多环芳烃,但未检测到HCl。根据裂解产物的种类及相对含量的变化,确定PVC的分段裂解回收工艺,从而提高了热裂解产物的回收率和热裂解效率。     

烟草中番茄红素热裂解产物对卷烟品质的影响

为了研究烟草中番茄红素热裂解产物对卷烟品质的影响,利用热裂解-气相色谱/质谱法模拟番茄红素在卷烟燃吸过程中产物的变化,研究在不同裂解氛围(空气氛围,N_2氛围)和不同裂解温度(300,600,900℃)下番茄红素的裂解产物及其对卷烟品质的影响,并对其机理进行了初步的探讨。结果表明,番茄红素在不同裂解条件下主要的裂解产物是甲苯、对-二甲苯、2,7-二甲基萘、1,3-二甲基萘、1,4,6-三甲基萘和2,3-二氢-1,1,3-三甲基-1H-茚等化合物,另外还生成6-甲基-5-庚烯-2-酮、苯甲醛、甲基苯甲醛、香叶醛、香叶基丙酮和假紫罗兰酮等香味化合物,这些物质随裂解温度和裂解氛围的不同其含量有所差异。     

裂解气相色谱-质谱法研究聚亚苯基砜的热裂解机理

在热重分析测试结果的基础上,采用裂解气相色谱-质谱联用仪(Py GC-MS)分析了聚亚苯基砜(PPSU)在500~700℃范围内不同温度下裂解形成的产物种类及其相对含量。结果发现:在500℃下,PPSU的分子链发生了裂解,不过形成的主要产物是苯酚,而不是二氧化硫。随着裂解温度升高,裂解产物种类越来越多,主要有对联苯基苯醚、二氧化硫、二苯醚、苯和对苯基苯酚等,并且二氧化硫逐渐成为相对含量最高的产物。最后根据不同温度下形成的裂解产物的种类及其相对含量推测了PPSU产生热裂解的机理。     

一种源自烟草的糖苷类化合物及其热裂解分析

通过现代分离纯化技术,从玉溪产K326烟叶中分离得到一种糖苷类化合物,结合一维核磁共振技术确定其为香兰素-β-D-葡萄糖苷。通过热重-差热分析(TG-DTG)和热解-气相色谱/质谱法(Py-GC/MS)对香兰素-β-D-葡萄糖苷在加热非燃烧型卷烟加热温度下的热失重行为及热裂解产物进行了研究,以评估其在加热非燃烧型卷烟中的潜在应用价值。结果表明:(1)香兰素-β-D-葡萄糖苷在500℃以下有两个失重过程,这两个失重过程的最大失重速率分别出现在237.60℃和291.97℃,两个失重温度均在加热非燃烧卷烟加热温度范围内(低于500℃);(2)在150~500℃下,裂解产物数量随裂解温度升高而增加,主要为苯类、醛类和环戊烯(酮)类,其中含量最高的为香兰素;(3)在200~300℃的加热温度下,该糖苷类潜香物质失重比较充分,并产出具有较高有效转化率的香气物质——香兰素,同时酚类和醛类的产生量相对较少。     

2,3-吡嗪二甲酸二顺-6-壬烯酯的合成、热裂解分析及其卷烟加香应用

以顺-6-壬烯醇和2,3-吡嗪-二甲酸为原料,以环己基碳二亚胺(DCC)为缩水剂,在4-二甲氨基吡啶(DMAP)催化作用下,合成了2,3-吡嗪-二甲酸二顺-6-壬烯酯。其结构经IR,1HNMR,13CNMR,HRMS图谱对比得到验证,并对其进行了热裂解和卷烟加香实验。结果表明:(1)合成产物为目标产物;(2)裂解温度对合成产物的热裂解产物的种类和含量有较大影响,随着裂解温度的升高,裂解程度愈来愈剧烈;(3)目标产物在卷烟中的适宜添加量为0.01%,目标产物加入到卷烟中后能够明显改善卷烟的吸食品质,协调烟香,减少刺激性和杂气,改善余味。     

Evaluation of two different scrap tires as hydrocarbon source by pyrolysis

The main objective of the present study is to investigate the effect of the polymer types in scrap tires on the pyrolysis products. Two different types of scrap tires (passenger car tire, PCT and truck tire, TT) have been pyrolyzed in a fixed bed reactor at the temperatures of 550, 650 and 800 °C under N₂ atmosphere. Pyrolysis products (gas, oil and carbon black) obtained from PCT and TT were investigated comparatively. The gaseous products were analyzed by GC–TCD. The psychical and chemical properties of pyrolytic oils were characterized by means of GC–FID, GC–MS, ¹H NMR. In addition, boiling point distributions of hydrocarbons in pyrolytic oils were determined by using simulated distillation curves in comparison with commercial diesel fuel. The production of activated carbon from pyrolytic carbon blacks (CBp) was also carried out. The composition of gaseous products from pyrolysis of PCT and TT were similar and they contained mainly hydrocarbons (C₁–C₄). Pyrolytic oils were found lighter than diesel but heavier than naphtha. The physical properties of pyrolytic oils from PCT and TT were similar at the same temperature. However, the composition of aromatic and sulphur content from pyrolysis of PCT was higher than that of TT. Furthermore, TT derived pyrolytic carbon black was found more suitable for the production of activated carbon due to its low ash content.     

烟用包装胶的应用现状及发展前景

介绍了烟用包装胶的粘接特性。从烟用包装胶的上机适应性及生物安全性角度出发,对目前国内PVAc(聚醋酸乙烯)乳液胶粘剂、EVA(乙烯-醋酸乙烯共聚物)热熔胶等高速包装胶的研究发展状况、卷烟企业对包装胶的实际需求、包装胶存在的问题以及发展趋势等内容进行了讨论。     

Influence of the filler material on the thermal stability of one‐component moisture‐curing polyurethane adhesives

Filler materials are part and parcel for the adjustment of adhesives, in particular, their rheological and mechanical properties. Furthermore, the thermal stability of adhesives can be positively influenced by the addition of an expedient filler, with inorganic types common practice in most cases. In this study, one‐component moisture‐curing polyurethane adhesives for engineered wood products based on isocyanate prepolymers with different polymer‐filled polyether polyols were investigated with regard to the filler's potential to increase the thermal stability of bonded wood joints. The property changes due to the addition of fillers were determined by means of mechanical tests on bonded wood joints and on pure adhesive films at different temperatures up to 200°C. Additional analyses by atomic force and environmental scanning electron microscopy advanced the understanding of the effects of the filler. The tested organic fillers, styrene acrylonitrile, a polyurea dispersion, and polyamide, caused increases in the cohesive strength and stiffness over the whole temperature range. However, the selected filler type was hardly important with regard to the tensile shear strength of the bonded wood joints at high temperatures, although the tensile strength and Young's modulus of the adhesive films differed over a wide range. Prepolymers with a lower initial strength and stiffness resulted in worse cohesion, in particular, at high temperatures. This disadvantage, however, could be compensated by means of the filler material. Ultimately, the addition of filler material resulted in optimized adhesive properties only in a well‐balanced combination with the prepolymer used. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Rheological investigation of cure kinetics and adhesive strength of polyurethane acrylate adhesive

In this work, we used rheological techniques to study both the cure characteristics and the degree of cure of polyurethane acrylate adhesive, a type of reactive adhesive used in hard disk component assembly. These results were then correlated with the tensile shear strengths of adhesives. Here, the cure characteristics of polyurethane adhesive were investigated at isothermal conditions ranging from 25 to 120°C. From the rheological results, the gelation time, the vitrification time, as well as the time required to reach the maximum degree of cure, decreased when increasing the curing temperature. The cure rates of adhesive increased with temperature in three temperature ranges, which were retardation zone, vitrification zone, and reaction‐controlled zone. The cure rates in these zones were controlled by slow diffusion, fast diffusion, and the rate of reaction, respectively. From the temperature sweep of fully‐cured adhesives, we found that the crosslinking level of adhesives increased with curing temperatures at different rates depending on the temperature zones as well. Moreover, the adhesive strength measured by tensile shear test was found to also increase correspondingly with the adhesives' T_g, indicating that the crosslinking level directly affected the adhesive strength. The strong dependence of adhesive strength with crosslinking level indicates that the crosslinking level was essential for high adhesive strength. The correlation of cure characteristics and adhesive strengths at various curing temperatures performed in this study can further provide useful information for planning appropriate curing schemes of polyurethane acrylate adhesives used in electronic and other industries. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

固化温度对缓凝黏合剂固化时间和强度的影响

为研究固化温度对缓凝黏合剂固化时间和强度的影响,将缓凝黏合剂在固化温度分别为25、45、65、85 ℃的条件下养护。通过邵氏硬度试验研究了3种缓凝黏合剂在不同固化温度条件下的固化速率,测试了缓凝黏合剂在不同固化温度条件下的拉伸剪切强度、抗折强度和抗压强度。结果表明,固化温度越高,缓凝黏合剂固化时间越短,以25 ℃为基准,45 ℃条件下的固化时间缩短约50 %,45 ℃以上,温度每升高20 ℃,固化时间缩短约10 %;以25 ℃条件下的强度为基准,缓凝黏合剂在不同固化温度条件下拉伸剪切强度的变化率在6 %内,抗折强度的增加率在6 %~45 %,抗压强度的增加率在9 %~50 %。     

Evaluation of wood bonding performance of water-washed cottonseed meal-based adhesives with high solid contents and low press temperatures

Water-washed cottonseed meal (WCSM) has been shown as a promising bio-based wood adhesive. In this work, we tested the bonding strength of WCSM slurries with high solid contents and low press temperatures per industrial input for non-structural applications as European Standard Class D1 wood adhesives. Increasing the WCSM content from 11 to 20% and 30% did not substantially change the adhesive strength but increased the viscosity of WCSM slurries dramatically. The shear strength at break of the maple wood pairs bonded at 40 and 60 °C was lower than that of maple pairs bonded at 100 °C. However, the shear strength of the pairs bonded at lower temperatures (40 and 60 °C) could be improved by extending the press time from 20 to 120 min. Addition of citric acid (CA) improved the viscosity of the WCSM adhesive at 20% solid content, but lowered the adhesive strength. The addition of denaturing reagent sodium dodecyl sulfate (SDS) showed reverse impacts on the adhesive strength and viscosity, compared to CA addition. Based on these observations, eight adhesive slurries were formulated with 20 and 30% of WCSM, 3% of CA or SDS, or 9.6% or 19.1% of denaturing reagent guanidine hydrochloride (GdmCl), and their bonding strengths were tested. These formulations could be used as the basis for developing low temperature WCSM-based wood adhesives to meet the criteria of both operational flowability and shear strength of the domestic furniture and small utensils niche markets for forest products.     

葡萄糖与组氨酸热解产物分析及其在卷烟纸中的应用

模拟卷烟纸及卷烟纸助剂燃烧、热裂解环境和条件,采用PY-GC-MS联机分析方法和卷烟感官评吸方法,进行L-组氨酸、葡萄糖及L-组氨酸和葡萄糖混料的热解产物对比分析及应用评价,结果表明:①在200,500,700℃热解温度条件下,L-组氨酸和葡萄糖混料能够产生大量杂环类致香物质,热解反应产物种类数量明显多于L-组氨酸和葡萄糖热解产物种类之和;②L-组氨酸和葡萄糖混料热解反应温度低于L-组氨酸和葡萄糖,且在200℃时就能够发生较为复杂的热解反应;③L-组氨酸和葡萄糖混料能够有效地提高卷烟纸的抽吸品质,增加卷烟香气的丰富性。     

Thermal degradation of reactive polyurethane hot melt adhesive based on MDI

The reactive polyurethane hot melt adhesive (HMPUR) was synthesized via bulk polymerization of poly(butyleneglycol adipate) (PBA), poly(ethylene orthophthalate) (PEO), poly(tetrahydrofurandiol) (PTMEG), 4,4′-methylene diphenyl diisocyanate (MDI) and pentaerythritol diacrylate (PEDA). Its thermal degradation was studied by thermogravimetry (TG) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). In helium atmosphere, the sample was pyrolyzed at three characteristic temperatures of 280, 450 and 600 °C according to the results of TG analysis. More than 20 characteristic volatile pyrolytic products were identified by on-line MS. The pyrolysis reaction types of HMPUR were proposed and verified through the analysis of pyrolytic products.     

Acetylene-terminated polyimide adhesives

In a research programme to develop an addition polyimide adhesive that is easily processed and exhibits good retention of strength after long term ageing, three different acetylene-terminated polyimide adhesives systems were prepared and characterized. The most promising system, a polyimidesulphone, was selected for a long term ageing study. The results indicate that this polyimidesulphone has improved strength retention over LARC-13 after ageing for extended time at high temperatures. In addition, it exhibited surprising adhesive strength for a short time at 593°C. The synthesis and characterization of these adhesives are discussed.     

Polyetherimide Adhesive

High-temperature adhesives which can be adhered at adhesive temperatures lower than those of conventional polyimide adhesives were investigated. Polyetherimide (PEI), developed by General Electric Co., is one such promising low curing temperature adhesive because it melts at temperatures lower than those used for conventional polyimides. Lap shear adhesive strength was investigated in a 75 μm-thick PEI film using steel test pieces. 350 kgf/cm² was achieved after curing for 1 hour at 270°C and 150 kgf/cm² was achieved at the test temperature of 200°C. PEI adhesive dissolved by N, N-dimethylformamide exhibited a high adhesive strength of 240 kgf/cm² after curing for 2 hours at 200°C. In addition, it was found that PEI could be used at much lower adhesive pressures than those of conventional polyimide adhesives.