Physical-Rheological Properties and Performances of Rejuvenated(Styrene-Butadiene-Styrene)Asphalt with Polymerized-MDI and Aromatic Oil

Traditional asphalt rejuvenators,like aromatic oil(AO),are known to be effective in improving the low-temperature properties and fatigue performances of aged SBS(styrene-butadiene-styrene)modified asphalt(SBSMA)binders and mixtures.However,these rejuvenators inevitably compromise their high-temperature properties and deformation resistances because they dilute asphalt binder but do not fix the damaged structures of aged SBS.In this study,a highly-active chemical called polymerized 4,4-diphenylmethane diisocyanate(PMDI)was used to assist the traditional AO asphalt rejuvenator.The physical and rheological characteristics of rejuvenated SBSMA binders and the moisture-induced damage and rut deformation performances of corresponding mixtures were comparatively evaluated.The results showed that the increasing proportion of AO compromises the hightemperature property and hardness of aged SBSMA binder,and an appropriate amount of PMDI works to compensate such losses;3%rejuvenator at mass ratio of AO:PMDI=70:30 can have a rejuvenated SBSMA binder with a high-temperature performance similar to that of fresh binder,approximately at 71.4°C;the use of AO can help reduce the viscosity of PMDI rejuvenated SBSMA binder for improving its workability;PMDI can help improve the resistance of AO rejuvenated SBSMA binder to deformation,especially at elevated temperatures,through its chemical reactions with aged SBS;moisture induction can enhance the resistance to damage of rejuvenated mixtures containing AO/PMDI or only PMDI;and the rejuvenator with a mass ratio of AO:PMDI=70:30 can lead the rejuvenated mixture to meet the application requirement,with a rut depth of only 2.973 mm,although more PMDI can result in a higher resistance of rejuvenated mixtures to high-temperature deformation.

高迁移率族蛋白B1对甲苯二异氰酸酯诱导的支气管上皮细胞中性粒细胞趋化因子CXCL12、IL-8表达的影响

目的通过体外实验探讨高迁移率族蛋白B1(high mobility group box 1,HMGB1)在甲苯二异氰酸酯(toluene diisocyanate,TDI)所致的职业性哮喘中趋化中性粒细胞的作用机制。方法制备TDI-人血清白蛋白(human serum albumin,HSA)偶联物(TDI-HSA),并通过Gutmann法与BCA法分别测定偶联物中TDI及HSA含量。分别以0、40、80、120 mg/L TDI-HSA染毒人支气管上皮细胞(human bronchial epithelial cells,HBECs)12 h,ELISA法检测细胞培养上清中白细胞介素-8(interleukin-8,IL-8)、趋化因子12(C-X-C motif chemokine 12,CXCL12)的水平;Western blot法检测细胞中HMGB1、CXCL12及核因子κB(nuclear factor kappa-B,NF-κB)相关蛋白的表达;活细胞荧光探针法检测活性氧(reactive oxygen species,ROS)的水平;免疫荧光法观察HMGB1的核转位情况。使用不同浓度(100、200 mmol/L)甘草素(glycyrrhizin,GL)预处理HBECs细胞24 h抑制HMGB1后,继续用TDI-HSA染毒12 h,检测细胞培养上清中IL-8水平,HMGB1、CXCL12及NF-κB相关蛋白表达,ROS释放水平及HMGB1的核转位情况。结果不同浓度TDI-HSA染毒HBECs 12 h后,随着染毒浓度的升高,HBECs细胞内HMGB1发生明显核转位,细胞中ROS和细胞上清中IL-8水平明显增加,差异有统计学意义(P<0.05);与对照组相比,120 mg/L染毒组HBECs细胞HMGB1、磷酸化P65蛋白表达显著增加,差异有统计学意义(P<0.05)。以含有不同浓度GL的培养基联合120 mg/L TDI-HSA处理HBECs细胞12 h后,与对照组相比,GL作用于HBECs细胞可显著抑制TDI-HSA导致的HMGB1的核转位,抑制HBECs细胞中的ROS和上清液中的IL-8水平的升高,显著减少细胞中HMGB1、磷酸化P65蛋白的表达,差异有统计学意义(P<0.05)。结论TDI可通过增加HBECs细胞HMGB1蛋白表达和核转位,激活NF-κB,促进IL-8的释放,不影响CXCL12的表达。GL可通过降低HMGB1表达,抑制NF-κB活化,减少IL-8释放水平。

六亚甲基二异氰酸酯与丙烯酸羟乙酯反应动力学及热动力学研究

研究了六亚甲基二异氰酸酯(HDI)与丙烯酸羟乙酯(HEA)在聚氨酯合成反应中的动力学和热动力学特征。在反应动力学方面,采用甲苯-二正丁胺滴定法获取了反应转化率数据,分别构建了二级动力学模型和Sato动力学模型来拟合实验数据。结果表明:该反应符合Van't Hoff近似规则;低转化率时,二级动力学模型拟合效果较好;而在高转化率时,由于存在自催化作用,Sato动力学模型具有更好的拟合优势;在热动力学方面,使用绝热加速量热仪(ARC)对反应放热进行了表征分析,结果显示该反应的热动力学反应级数为0.8,表观活化能为57.51 kJ/mol。该研究为聚氨酯的安全、高效和绿色合成提供了科学理论依据。

TDI-100与TMP催化聚合制备聚氨酯固化剂工艺研究

聚氨酯是由氰酸酯和羟基在一定温度下结合制备而成的,主要应用在胶粘剂当中。本文对甲苯二异氰酸酯(TDI-100)与三羟甲基丙烷(TMP)制备聚氨酯固化剂工艺进行了优化,充分考虑了在不同条件实验下产品的粘度、容忍度、游离TDI、-NCO含量参数,并考虑了高温引起的胶化问题。实验结果表明,在TDI-100与TMP的配比为1.95、加入催化剂后的反应温度65℃、反应时间5 h、催化剂加入量为0.08%(相当于TDI质量),磷酸作为终止剂时,其游离TDI量为0.4达到国家标准,容忍度为2.7 g/g,-NCO含量为13.9%,并且粘度适中不会发生胶化。

不同固化剂对浇注高聚物黏结炸药药浆固化时间的影响

为探究不同固化剂应用于浇注高聚物黏结炸药(polymer bonded explosives,PBX)药浆时的固化时间,利用傅里叶变换红外光谱仪、旋转流变仪及邵氏A型硬度计,研究了甲苯二异氰酸酯(TDI)、二聚酸二异氰酸酯(DDI)及TDI/DDI混合固化剂对浇注PBX药浆固化过程中的固化反应速率、适用期及固化时间的影响。结果表明,不同固化剂与端羟基聚丁二烯(HTPB)在55℃下的反应速率大小关系为k_(TDI)>k_(TDI/DDI)>k_(DDI),且反应遵循二级反应规律。对于高固含量的浇注PBX药浆,在固化比1.2、固化温度55℃的条件下,采用TDI固化剂时适用期为4 h,固化时间为72 h;采用DDI固化剂时,适用期能够达到5 h以上,但其固化时间为128 h;采用TDI/DDI混合固化剂时,固化时间缩短为96 h,适用期可以达到5 h以上,固化效果较为理想。

阴极电泳涂料用封闭型PDI固化剂的制备

首先以生物基五亚甲基二异氰酸酯(PDI)和三羟甲基丙烷为原料合成了PDI预聚体,再以甲乙酮肟为封闭剂对PDI预聚体的-NCO基团进行封端,合成封闭型PDI固化剂。将封闭型PDI固化剂应用于阴极电泳涂料,考察了固化剂的应用性能。结果表明:当PDI单体用量为1 mol,三羟甲基丙烷和甲乙酮肟的用量分别为0.45 mol和0.55 mol时,所制备的封闭型PDI固化剂状态良好,且固化剂与胺化环氧树脂配套制备的电泳乳液贮存稳定性良好,电泳漆膜可在135℃/20 min实现固化,漆膜性能满足HG/T 3952-2007要求。

气相色谱—质谱法测定聚氨酯塑胶跑道中间苯二甲基异氰酸酯(XDI)含量

本文建立了气相色谱-质谱联用技术测定聚氨酯塑胶跑道中间苯二甲基异氰酸酯(XDI)残留量的分析方法.样品用乙酸乙酯超声提取,提取液过滤后经(5%苯基)—甲基聚硅氧烷的毛细管柱分离,进入气相色谱-质谱仪测定,以外标法定量,得到了较宽的线性范围和较低的定量检出限.在优化萃取溶剂、色谱柱等检测条件下,间苯二甲基异氰酸酯的系列浓度为250—5000μg·L-1,相关系数(R2)在0.9999,检出限可达到0.02 mg·kg^(-1),定量限0.06 mg·kg^(-1),加标回收率在89.3%—93.4%之间,相对标准偏差范围在1.9%—2.8%(n=6).该方法简单、快捷、准确,满足了聚氨酯塑胶跑道中间苯二甲基异氰酸酯的残留量日常检验的要求.

Kinetics of the decomposition of dimethylhexane-1,6-dicarbamate to1,6-hexamethylene diisocyanate

The kinetics of the decomposition of dimethylhexane-1,6-dicarbamate to 1,6-hexamethylene diisocyanate was studied. A consecutive reaction model was established and the reaction orders for the two steps were confirmed to be 1 and 1.3 by the integral test method and the numerical differential method, respectively. The activation energies of the two steps were （56.94 4±5.90） kJ·mol^-1 and （72.07±3.47） kJ·mol^-1 with the frequency factors exp（ 12.53±1.42） min^- 1 and （ 14.254±0.84） tool^-0.33. L^0.33·min^-1, respectively. Based on the kinetic model obtained, the progress of the reaction can be calculated under given conditions.

CURE CHARACTERISTICS OF HYDROXYL TERMINATED POLYBUTADIENE PREPOLYMER WITH BLOCKED TOLUENE DIISOCYANATE-Ⅰ

Controlled release of TDI and hence the cure characteristics of several blocked TDI with HTPB are reported. The reactions were followed through viscosity measurements as a function of time and temperature under the catalytic influence of triethylamine. The effect of nature of substituents present on the end capping substrate, temperature, solvent, basicity of catalyst and kinetics thereon have been studied.

Determination of toluene diisocyanate in synthetic-rubber track by ion chromatography with ultraviolet detection after alkaline suppressor

In the present work, a novel analytical method was proposed for the determination of toluene diisocyanate （TDI） in syntheticrubber track by ion chromatography （IC） coupled with an ultraviolet detector setting at 212 nm. TDI can be hydrolyzed to toluene diamine （TDA） which can be separated by cation-exchange IC easily. The optimum IC separation was performed on an IonPac CS12A column （150 mm ×4.0 mm） using 20 mmol L^-1 sodium sulfate, 10 mmol L^-1 sulfuric acid and 10% acetonitrile as eluent. It was found that a higher signal response of TDA could be obtained under alkaline condition. A suppressor was used to change the acidic eluent into alkaline one. 0.8 mol L^-1 potassium hydroxide was chosen as the optimum regeneration eluent. With the added suppressor and regenerant, signal response was magnified by about 16 times and lower limit of detection （LOD, 0.13 μg L^-1） was obtained. Within-day relative standard deviation （R.S.D.） was less than 3.6%. The recoveries of TDI spiked in synthetic-rubber track samoles were 96.4-110.6%.

~1H NMR analysis of the tolylene-2,4-diisocyanate-methanol reaction

Tolylene-2,4-diisocyanate（2,4-TDI） 1 reacts with methanol through two simultaneous paths in the polyurethane reaction,which involve two different intermediates-tolylene-4-carbamatic-2-isocyanate 2 and tolylene-2-carbamatic-4-isocyanate 3,and the final product is tolylene-2,4-dicarbamate 4.The-CH_3 chemical shifts in benzene ring in compounds 1,2,3 and 4 can be easily tested and well distinguished,through which those four compounds are quantified and their kinetics are investigated.It shows that four rate constants for the tolylene-2,4-diisocyanate-methanol reaction in CCl_4 at 50℃are k_1=9.6×10^（-2）h^（-2）mol^（-2）min^（-1）, k_2=1.4×10^（-2）h^（-2）mol^（-2）min^（-1）,k_3=4.0×10^（-3）h^（-2）mol^（-2）min^（-1）,k_4=1.4×10^（-3）h^（-2）mol^（-2）min^（-1）.（k_1 is the reaction rate constant from compounds 1 to 2;k_2 is the reaction rate constant from compounds 1 to 3;k_3 is the reaction rate constant from compounds 3 to 4;k_4 is the reaction rate constant from compounds 2 to 4）.

DIBUTYLTIN DILAURATE-CATALYZED DIISOCYANATE COUPLING—GRAFTING OF POLY(ETHYLENE GLYCOL)ONTO NANO-SILICA SURFACE THROUGH A ONE-STEP PROCEDURE

Grafting polymer glycols onto nano-silica surface through one-step procedure was investigated.The major characteristic of this procedure is that all the materials and reagents(silica,PEG,TDI,DBTDL,solvent)required for grafting were added simultaneously into the reaction vessel.TDI and DBTDL were used as coupling agent and catalyst,respectively. The products were characterized by FTIR,TGA,elemental analyses and TEM,giving evidence for successful grafting of PEG.Possible mechanism of this grafting was studied and two grafting processes were proposed.The process through which the grafting proceeds depends on the reaction temperature.Effect of molecular weight of PEG on grafting was also investigated.

The Curing for Modified Vinyl Ester Resin by Hexamethylene Diisocyanate and Its Influence on Performances

The commercial vinyl ester resins(VER)was modified by diphenylmethane diisocyanate(MDI)to enhance its toughness,which is called MVER.Hexamethylene diisocyanate(HDI),a common curing agent for polyurethane(PU),was found to be a reactive agent for MVER and can contribute to the toughness of MVER.Based on present experiment results,the crosslinking mechanism of MVER and HDI system is very similar to that of PU.The FTIR result shows the-NCO of HDI can react with the-OH of MVER.The microstructure of material prepared by MVER and HDI was characterized by NMR,and it was revealed that the unique microstructure leads to the good performances.The different content of HDI has an influence on the microstructure,and the microstructure gradually reduces the toughness and mechanical performances of the MVER cured with increasing concentration of reactive curing agent(HDI).This feature is consistent with a maximum in toughness as a function of the additive(HDI)content,followed by a rapid deterioration in toughness at higher concentrations.The toughness exhibits the maximum at such an HDI concentration(20wt%).Therefore,the special curing agent(HDI)and reactive mode is very important to the microstructure and mechanical properties of material.Furthermore,there should be other reactions which contribute to the curing and microstructure of the material,which needs the further research.

CURE CHARACTERISTICS OF HYDROXYL TERMINATED POLYBUTADIENE PREPOLYMER WITH BLOCKED TOLUENE DIISOCYANATE-Ⅱ

Cure characteristics of hydroxyl terminated polybutadiene (HTPB) prepolymer with avariety of blocked toluene diisocyanate (TDI) in the presence of triethylamine (TEA) andchloroacetic acid catalyst are reported. Phenol, thiophenol, p-chloropheno1, p-nitrophenol,p-cresol, resorcinol, naphthols, caprolactam and butylated-hydroxytoluene were used as blockingagents. Viscosity measurements have been carried out using a mixture of HTPB and blocked TDIin cyclohexanone in the presence of the catalysts at 50℃ and 60℃ using Haake rotational vis-cometer. Viscosity measurements have also been carried out with 50% solids such as ammonium sulphate along with HTPB and TDI adduct.

Non-phosgene synthesis of hexamethylene-1,6-diisocyanate from thermal decomposition of hexamethylene-1,6-dicarbamate over Zn–Co bimetallic supported ZSM-5 catalyst

A non-phosgene route for the synthesis of hexamethylene-1,6-diisocyanate(HDI) was developed via catalytic decomposition of hexamethylene-1,6-dicarbamate(HDC) over Zn–Co bi-metallic supported ZSM-5 catalyst.The catalyst was characterized by FTIR and XRD analyses. Three solvents dioctyl sebacate(DOS), dibutyl sebacate(DBS) and 1-butyl-3-methylimidazolium tetrafluoroborate(BMIMBF_4) were investigated and compared; DOS gave better performance. The catalytic performances for thermal decomposition of HDC to HDI using DOS as solvent were then investigated, and the results showed that, under the optimized reaction conditions, i.e.,10 wt%concentration of HDC in DOS, 250 °C temperature, 60 min reaction time, 83.8% yield of HDI had been achieved over Zn–Co/ZSM-5. Decomposition of the intermediate hexamethylene-1-carbamate-6-isocyanate(HMI) over Zn–Co/ZSM-5 in DOS solvent was further studied and the results indicated that yield of HDI from HMI reached to 69.6%(98.6% HDI selectively) at 270 °C, which further increased the yield of the total HDI(HDI_(tol)) to as high as 95.0%. Recycling of catalyst showed that HDI and HMI yield slightly decreased, and by-product yield increased after the catalyst was reused for 4 times. At last possible reaction mechanism was proposed.

Synthesis and Properties of Organic-Inorganic Hybrid Porous Polymers Obtained with Click Addition Reactions of Thiol-Functionalized Random Type Silsesquioxane by and Diacrylate or Diisocyanate Compounds

Organic-inorganic hybrid network polymers have been synthesized by addition reaction of a thiol-functionalized random type silsesquioxane (SQ109) and alkyl diacrylate or diisocyanate compounds. Thiol-ene reaction of SQ109 and 1,4-butanediol diacrylate (BDA) successfully yield porous polymer in toluene initiated by azobis(isobutyronitrile) (AIBN) at 60°C. Morphology of the porous polymers was composed by connected globules, and the diameter of the globules decreased with increasing in the monomer concentration of the reaction system. By contrast, the reaction with 1,6-hexanediol diacrylate or 1,5-hexadiene yielded homogeneous clear gels. Thermal analyses of SQ109-BDA porous polymers indicated that thermal degradation of ester groups of BDA in the polymer network occurred at around 300°C. The porous polymer was also obtained by the reaction using a photo-initiator (Irugacure184) at room temperature, and showed higher Young’s modulus than the corresponding porous polymer obtained with the reaction with AIBN due to the small size of the globules. Young’s modulus of SQ109-BDA porous polymer increased with increasing in the monomer concentration of the reaction systems. Thiolisocyanate addition reactions between SQ109 and hexamethylene diisocyanate (HDI) or methylenediphenyl 4,4’-diisocyanate (MDI) were investigated to obtain network polymers. The reactions in toluene yielded the corresponding homogeneous clear gels. By contrast the reactions in a mixed solvent of toluene (50 vol.%) and N,N-dimethylformamide (50 vol.%) produced porous polymers. The morphology of the porous polymers was composed by connected globules or aggregated particles. The size of globules and particles in the SQ109-HDI porous polymers was larger than those in the SQ109-MDI porous polymers. Thermal degradation of SQ109-HDI and SQ109-MDI porous polymers started at round 260°C and showed endothermic peak at around 350°C derived from degradation of thio-urethane bond.

An efficient green route for hexamethylene-1,6-diisocyanate synthesis by thermal decomposition of hexamethylene-1,6-dicarbamate over Co3O4/ZSM-5 catalyst： An indirect utilization of CO2

The utilization of CO2 as raw material for chemical synthesis has the potential for substantial economic and green benefits. Thermal decomposition of hexamethylene-1,6-dicarbamate （HDC） is a promising approach for indirect utilization of CO2 to produce hexamethylene-1,6-diisocyanate （HDI）. In this work, a green route was developed for the synthesis of HD1 by thermal decomposition of HDC over Co3O4/ZSM-5 catalyst, using chlorobenzene as low boiling point solvent. Different metal oxide supported catalysts were prepared by incipient wetness impregnation （IWI）, PEG-additive （PEG） and deposition precipitation with ammonia evaporation （DP） methods. Their catalytic performances for the thermal decomposition of HDC were tested. The catalyst screening results showed that Co3O4/ZSM-525 catalysts prepared by different methods showed different performances in the order of Co3O4/ZSM-5 25（PEG） 〉 Co3O4/ZSM-525（IWI） 〉 Co3O4/ZSM-525（DP）. The physicochemical properties of Co3O4/ZSM- 52s catalyst were characterized by XRD, FTIR, N2 adsorption-desorption measurements, NH3-TPD and XPS. The superior catalytic performance of Co3O4/ZSM-52S（PEG） catalyst was attributed to its relative surface content of Co3 ＋, surface lattice oxygen content and total acidity. Under the optimized reaction conditions： 6.5% HDC concentration in chlorobenzene, 1 wt% Co3O4/ZSM-525（PEG） catalyst, 250℃ temperature, 2.5 h time, 800 ml.min 1 nitrogen flow rate and 1.0 MPa pressure, the HDC conversion and HDI yield could reach 100% and 92.8% respectively. The Co3O4/ZSM-525（PEG） catalyst could be facilely separated from the reaction mixture, and reused without degradation in catalytic performance. Furthermore, a possible reaction mechanism was proposed based on the physicochemical properties of the Co3O4/ZSM-5 25 catalysts.

四羧酸配体构筑锌荧光配位聚合物的结构表征

配位聚合物(CPs)由于具有多样化的结构,以及在光化学、分子磁体、异相催化和气体吸附与分离等方面具有潜在应用而受到关注,特别是如何构建新型的CPs至关重要。利用半刚性四羧酸类配体5,5′-(羰基二氮杂二烯基)二异氰酸(H4L)和锌盐,通过溶剂热法合成一个新三维CPs:({[Zn2(L)2(H2O)6]·[Zn(H2O)6]·4H2O}n),并对CPs进行详细表征。在配位聚合物中,Zn(Ⅱ)离子通过与L4-阴离子桥联得到之字型一维链,一维链结构中的配位水、游离水以及Zn(H2O)6进一步通过氢键作用连接相邻的一维链,最终得到一个三维超分子框架结构。热重分析显示CPs具有良好的热稳定性,固体荧光显示CPs有较好的荧光强度和适中的激发/发射波长,因此该CPs是潜在的光学材料。