微波辐射合成环境友好型高分子陶瓷添加剂的研究

报告首先就目前传统缓释剂的研究现状进行了分析,并提出以后的三个发展方向,重点介绍了采用微波辐射技术,以天然有机质腐植酸的钠盐为原料,马来酸酐(MA)为改性单体合成环境友好陶瓷添加剂NaHA-co-MA的研制过程,该产品能提高陶瓷料浆的流动性、坯体强度和可塑性,为今后环境友好型陶瓷添加剂的开发研究提供重要参考。     

HANa-AANa共聚物作为多功能陶瓷添加剂的研究

通过自由基水溶液微波共聚法合成了腐植酸钠-丙烯酸钠(HANa-AANa)共聚物,将之应用于陶瓷料浆及坯体中,研究了HANa-AANa共聚物对陶瓷料浆流动性、坯体可塑性及坯体干燥强度的影响。通过和腐植酸钠的对比研究表明,HANa-AANa共聚物是一种较好的陶瓷多功能添加剂,对料浆具有良好的解凝性,同时对坯体具有较大的增塑、增强效果。     

叔丁基乙烯基醚/马来酸酐共聚物的合成及表征

以叔丁基乙烯基醚(t-BVE)和马来酸酐(MA)为原料,偶氮二异丁腈(AIBN)为引发剂,采用沉淀聚合方法制备了叔丁基乙烯基醚-马来酸酐共聚物(P-BVE/MA)。分别讨论了引发剂加入量、单体浓度及反应温度等聚合参数对产品叔丁基乙烯基醚-马来酸酐共聚物特性黏度(SV)及收率的影响,获得了最优的聚合条件。采用傅里叶红外光谱(FT-IR)和核磁共振波谱(NMR)等测试手段对所聚合产品进行了表征,结果表明所制备的叔丁基乙烯基醚-马来酸酐共聚物为交替共聚物。     

自制聚丙烯酸钠用作陶瓷助磨减水剂和增强剂

用磷酸钠取代常见链转移剂异丙醇,在引发剂w(过硫酸钠)=5.0%,链转移剂w(磷酸钠)=33%,单体φ(丙烯酸)=50%,和反应温度55℃的条件下,合成了相对分子质量1 500的聚丙烯酸钠。产物的红外光谱说明,丙烯酸单体已完全聚合,产物中有磷酸根与亚甲基的键合作用。相对分子质量为1 500的聚丙烯酸钠是一种高效的陶瓷助磨减水剂和增强剂,能使泥浆的黏度降低到180 MPa.s,使泥浆的200目筛余物质量分数降低到0.4%,使坯体干燥强度增强率提高到280%。     

聚羧酸高效陶瓷减水剂的合成及性能

以马来酸酐(MA)、丙烯酸(AA)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为单体,采用水溶液聚合法制备了一种线型MA/AA/AMPS聚羧酸高效陶瓷减水剂。通过正交实验,研究了各反应条件对添加了0.35%(相对于绝干料浆质量)线型MA/AA/AMPS聚羧酸高效陶瓷减水剂的陶瓷坯体料浆流动时间的影响,并进一步利用FTIR和XRD等手段对线型MA/AA/AMPS聚羧酸高效陶瓷减水剂的官能团结构和晶相结构进行了表征,分别用POM和SEM照片观察陶瓷坯体料浆的分散情况和陶瓷坯体试样的断面形貌。结果表明,线型MA/AA/AMPS聚羧酸高效陶瓷减水剂最佳合成条件为:聚合温度为80℃、引发剂用量占聚合单体总质量的9%、n(MA)∶n(AA)∶n(AMPS)=1.0∶3.5∶1.5、聚合时间为4 h。当线型MA/AA/AMPS聚羧酸高效陶瓷减水剂掺量为0.35%(相对于绝干料浆质量)时,陶瓷坯体料浆体系的黏度从689.5 mPa·s降低到56.8 mPa·s。     

自制聚丙烯酸钠复合陶瓷坯体增强剂的应用

自制了聚丙烯酸钠复合坯体增强剂,研究了它对陶瓷坯体强度和地砖生产成品率的影响。复合坯体增强剂在质量分数为0 2%～0 4%时,对陶瓷坯体增强作用最大。当复合增强剂4号质量分数为0 2%时,陶瓷坯体强度增强率达到215 38%,而聚丙烯酸钠质量分数为0 6%时,增强率只有151 64%。自制增强剂的增强作用使地砖生产的成品率从67 70%提高到90%以上。     

异丁烯-马来酸酐共聚物的合成研究

以马来酸酐(MA)和异丁烯(IB)为原料,采用自由基溶液聚合方法合成MA-IB共聚物.筛选了溶剂体系和引发剂类型,并考察了反应温度、引发剂用量和单体质量分数对聚合产物的分子质量的影响,最后研究了不同分子质量的产品对分散氧化铁性能的影响.结果表明:在单体质量分数为40％,反应温度为70℃,引发剂用量为1％的条件下合成的MA-IB产品具有较好的性能.     

改性EPDM与二烯类橡胶的共硫化

在引发剂存在下用高温密炼机制得了马来酸酐(MA)改性EPDM。红外光谱分析表明,MA与EPDM分子发生化学结合。研究了MA改性EPDM与SPR、NR和NBR共混硫化胶的性能。与未改性EPDM相比,MA改性明显改善了EPDM与二烯类橡胶的共硫化性和共混硫化胶的力学性能。     

基于正交试验设计的聚羧酸高效陶瓷减水剂性能

以马来酸酐(MA)、丙烯酸(AA)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为单体,采用水溶液聚合法制备了一种线型MA/AA/AMPS聚羧酸高效陶瓷减水剂。通过正交试验,研究了各反应条件对添加了0.35%(相对绝干料浆)线型MA/AA/AMPS聚羧酸高效陶瓷减水剂的陶瓷坯体料浆流动时间的影响,并进一步利用FT-IR和XRD等手段分别对线型MA/AA/AMPS聚羧酸高效陶瓷减水剂的官能团结构和晶相结构进行表征,分别用POM和SEM照片观察陶瓷坯体料浆的分散情况和陶瓷坯体试样的断面形貌。结果表明,线型MA/AA/AMPS聚羧酸高效陶瓷减水剂最佳合成条件为：聚合温度为80 ℃、引发剂用量占聚合单体总质量的9%、n(MA)∶n(AA)∶n(AMPS)=1.0∶3.5∶1.5和聚合时间为4 h。当线型MA/AA/AMPS聚羧酸高效陶瓷减水剂掺量为0.35%(相对绝干料浆)时,陶瓷坯体料浆体系的黏度从689.5 mPa穝降低到56.8 mPa穝。     

新型陶瓷坯体增强剂的应用研究

主要研究了自制的以木质素为主要原料的陶瓷坯体增强剂的应用。考察了不同浓度、不同原料的增强剂对泥浆流动性,生坯强度,以及烧成后瓷砖黑心现象的影响。结果表明,自制木质素基的增强剂,引入到建筑陶瓷坯体配方中,不仅可以明显提高生坯强度,而且具有一定的解凝效果,对泥浆流动性影响不大。     

Kinetics and mechanism of free radical grafting of methyl acrylate onto sago starch

The graft copolymerization was carried out by methyl acrylate with sago starch in which ceric ammonium nitrate was used as an initiator. It has been found that the rates of graft polymerization and grafting efficiency were dependent upon the concentration of ceric ammonium nitrate (CAN), methyl acrylate (MA), sago starch (AGU, anhydro glucose unit), mineral acid (H₂SO₄), and as well as reaction temperature and period. A rate equation of polymerization was established from the proposed reaction mechanism, and the rate of polymerization (R_p) was the first‐order dependence of the MA monomer concentration and square root of the CAN concentration. A new kinetic model of the grafting reaction has been proposed, and a normal kinetics of methyl acrylate polymerization was observed. An equation of a predicted model relating the graft fraction of poly(methyl acrylate) with the sago starch has been derived, and validity of the predicted model was verified by the experimental results. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 784–791, 2000     

Graft-copolymerization of glycidyl methacrylate onto cotton cellulose

Glycidyl methacrylate was graft-copolymerized onto cotton cellolose using both photo-and chemical-initiation techniques using different initiators. The photoinitiators used were uranyl nitrate, ceric ammonium nitrate, and benzoin ethyl ether, whereas the chemical initiators used were ceric ammonium nitrate and potassium persulfate. Optimization of various parameters of grafting, viz., time, temperature, initiator, and monomer concentrations, was carried out. Ceric ammonium nitrate gave the maximum and almost identical values of graft add-on, by both grafting techniques, at equivalent cocentration of the monomer. Use of optimized conditions of ceric ammonium nitrate-photoinitiated grafting for sodium hydroxide-swollen substrate as well as for grafting baths incorporating acids enhanced the graft level. © 1994 John Wiley & Sons, Inc.     

Graft copolymerization of acrylonitrile onto hemicellulose using ceric ammonium nitrate

The ability of ceric ammonium nitrate to induce graft copolymerization of acrylonitrile onto hemicellulose was investigated. The graft yield depends on monomer and initiator concentrations as well as reaction time and temperature. Chemical analysis of the reaction product of hemicellulose and acrylonitrile in the presence of ceric ammonium nitrate revealed that the ceric ammonium nitrate acted as initiator for polymerization of acrylonitrile and as oxidizing agent for hemicellulose. Proof for grafting of hemicellulose was provided through IR analysis.     

高纯硝酸铈铵的合成与应用研究

研究了以碳酸铈和乙酸为主要原料，合成硝酸铈铵和乙酸钠的集成工艺。讨论了前驱体氢氧化铈的硝酸溶解性能、硝酸铈铵结晶母液的循环利用、结晶母液中铈的回收方法。从原料碳酸铈到最终产物硝酸铈铵，铈的总收率为95．61％。以硝酸铈铵为引发剂，引发了丙烯酸与壳聚糖的接枝共聚反应，接枝率为45．69％。     

Synthesis and Characterization of Carboxymethyl Chitosan Grafted Methacrylic Acid Initiated by Ceric Ammonium Nitrate

O-carboxymethyl chitosan (CMCH) was prepared and characterized by FTIR spectroscopy and X-ray diffraction. Grafting of methacrylic acid (MA) onto CMCH using ceric ammonium nitrate (CAN) as an initiator was carried out under nitrogen atmosphere in aqueous solution. Evidence of grafting was confirmed by comparison of FTIR spectra of CMCH and the grafted copolymer as well as scanning electron micrograph (SEM) and X-ray diffraction of the products. The effects of concentration of CAN, MA, reaction time and temperature on graft copolymerization were studied by determining the grafting percentage and grafting efficiency. Keeping other conditions constant, the optimum grafting conditions were obtained as follows: CMCH = 2 gm, CAN = 0.2 M and MAA = 0.581 mol/L, reaction temperature = 40°C and reaction time = 4.5 hr.     

Graft copolymerization of methyl acrylate onto sago starch using ceric ammonium nitrate as an initiator

The graft copolymerization of methyl acrylate onto sago starch was carried out by a free radical initiating process. The free radicals were produced by the chemical initiation method in which ceric ammonium nitrate was used as an initiator. It was found that the percentages of grafting, grafting efficiency, and rate of grafting were all dependent on the concentration of ceric ammonium nitrate (CAN), methyl acrylate (MA), sago starch (AGU), mineral acid (H₂SO₄), and reaction temperature and period. The variables affecting the graft copolymerization were thoroughly examined. The optimum yield of grafting was obtained when the concentration of CAN, MA, AGU, and H₂SO₄ were used at 8.77 × 10⁻³, 0.803, 0.135, and 0.175 mol L⁻¹, respectively. The optimum reaction temperature and period were 50°C and 60 min, respectively. The rate of graft polymerization was explored on the basis of experimental results and reaction mechanism. The evidence of grafted copolymers was investigated by using FTIR spectroscopy, TG, and DSC analysis. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 516–523, 2000     

聚乙二醇相转移催化合成3-硝基水杨醛

在醋酸、相转移催化剂聚乙二醇-400存在下,水杨醛与硝酸铈铵反应生成3-硝基水杨醛。最佳反应条件为:n(水杨醛)∶n(硝酸铈铵)∶n(聚乙二醇-400)=1∶1∶0.056,反应温度为40℃,反应时间为1.6 h,产率达76.6%。聚乙二醇-400可循环使用5次,催化活性基本不变。     

微波辐射下1,3-二硝基-2-萘酚的合成

微波辐射下,2-萘酚与硝酸铈铵在醋酸和聚乙二醇溶液中反应生成1,3-二硝基-2-萘酚。提供了一种温和的、简便的制备1,3-二硝基-2-萘酚的一种新方法。结果表明最佳反应条件为:2-萘酚与硝酸铈铵的物质的量比为1∶1.2,辐射功率:30 W:辐射爬升时间:4.00 min;微波反应时间:4.00 min;温度:45℃(最大54℃);压力:207 kPa;1,3-二硝基-2萘酚的产率达76.4%。     

相转移法合成5-硝基苊

在醋酸、相转移催化剂聚乙二醇存在下 ,苊与硝酸铈铵反应生成 5 -硝基苊。反应条件温和 ,产率较高。硝酸铈铵是一种选择性良好 ,具有多方面用途的试剂。讨论了硝酸铈铵、醋酸、聚乙二醇的用量以及反应温度、时间对反应的影响。从而选出最佳反应条件     

Grafting onto wool. VII. Ceric ion-initiated graft copolymerization of vinyl monomers. Comparison of monomer reactivities

In an attempt to compare relative reactivities of vinyl monomers toward grafting, methyl methacrylate (MMA) and acrylic acid (AAc) were grafted separately to Himachali wool in aqueous medium by using ceric ammonium nitrate (CAN) as redox initiator. Nitric acid was found to catalyze the reaction. Percent grafting was determined as a function of concentration of nitric acid, concentration of CAN, concentration of monomer, time, and temperature. Optimum conditions for maximum grafting were evaluated for each monomer and were found to depend upon the nature of the monomer. Reactivities of MMA and AAc toward grafting were compared with those of methyl acrylate (MA), ethyl acrylate (EA), and vinyl acetate (VAc) reported earlier from this laboratory and were found to follow the order MA > EA > MMA > VAc > AAc. An explanation for the observed order of reactivity of different vinyl monomers is presented.