天然氨基酸引发六元环碳酸酯开环聚合的研究

研究了多种天然氨基酸存在下2,2-二甲基三亚甲基环碳酸酯(DTC)和三亚甲基环碳酸酯(TMC)的开环聚合反应。其中中性两官能团氨基酸作用下所得到聚合物的分子量和产率最高,在反应温度110°C、反应时间60h、DTC与L-苯丙氨酸摩尔比为200∶1的条件下,得到数均分子量为18900g.mol-1的聚(2,2-二甲基三亚甲基碳酸酯);在反应温度90°C、反应时间24h、TMC与L-亮氨酸摩尔比为100∶1的条件下,得到数均分子量为15000g.mol-1的聚(三亚甲基碳酸酯)。     

微波辅助法合成高分子量聚丙烯酰胺

以丙烯酰胺(AM)为单体,水为溶剂,过硫酸铵(APS)和偶氮二异丁基脒盐酸盐(AIBA)为复合引发体系,采用微波辅助法制备聚丙烯酰胺(PAM)。研究了微波辐照功率、辐照时间、单体浓度、引发剂用量对聚丙烯酰胺分子量和单体残留率的影响,采用红外光谱(FT-IR)表征了聚合物产物结构,最后考察了剪切作用对PAM性能的影响。结果表明:采用微波辅助法制备的PAM反应时间短、能耗低、分子量高、单体残留率低;当微波功率为100 W,辐照时间为8 min,单体浓度为25%,引发剂用量为0.05%时产物分子量可达1050×104,并且单体残余量低;PAM的降解随着剪切时间的延长和剪切速度的加快而加快。     

微波诱导催化氧化剩余污泥的研究

以活性炭为催化剂,对微波诱导氧化剩余污泥过程中污泥性质的变化进行了研究.结果表明,在微波辐照功率为800 W、微波辐照时间为60 s、SS的活性炭投加量为0.3 g·g~(-1)时,污泥溶解率达到28.9%,同单独微波处理污泥相比,污泥溶解率增大10%.在此操作条件下,更多的微生物胞外聚合物分解、胞内物质释放到液相中,使污泥上清液中溶解性有机物含量明显增加.污泥破解后,磷释放到溶液中,使TP的质量浓度增加了1.4倍.在微波辐照活性炭产生的高温及氧化剂作用下,部分有机氮被矿化,NH4_4~+-N的质量浓度由7.9增至14.2 mg·L~(-1).     

微波辐射下酸性离子液体促进氧杂蒽二酮类衍生物的合成

以芳香醛和1,3-环己二酮或5,5-二甲基-1,3-环己二酮为原料,在微波辐射条件下,酸性离子液体[bmim]HSO4作催化剂,合成了一系列的氧杂蒽二酮类衍生物。该方法具有操作简便、反应时间短、产率较高、反应体系对环境友好、催化剂可回收重复使用等优点。     

ZnCl_2-微波活化法制备秸秆基活性炭

研究了氯化锌微波活化法在不同操作条件下制备秸秆基活性炭,探讨了最佳预处理温度、氯化锌的浓度、微波功率和微波辐照时间对活性炭性能的影响。最佳工艺条件为:预处理温度为350℃,氯化锌溶液的质量分数为40%,微波活化功率为550 W,微波辐照时间为6min。对所制得的活性炭进行苯酚吸附、亚甲基蓝吸附和红外光谱及电镜等分析检测。实验最终产率达到40%以上,亚甲基蓝吸附值为70mg/g以上。     

磷酸-微波活化法制备秸秆基活性炭

研究了磷酸微波活化法在不同操作条件下制备秸秆基活性炭,探讨了最佳预处理温度、磷酸的浓度、微波功率和微波辐照时间对活性炭性能的影响。最佳工艺条件为:预处理温度为500℃,磷酸溶液的质量分数为25%,微波活化功率为450 W,微波辐照时间为5 min。对所制得的活性炭进行苯酚吸附、亚甲基蓝吸附和红外光谱及电镜等分析检测。实验最终产率达到35%以上,亚甲基蓝吸附值为150 mg/g以上。     

微波辐照法合成1,3-双（3-三乙氧基硅丙基）-咪唑氯鎓

比较了三种常规合成方法制备1,3-双(3-三乙氧基硅丙基)-咪唑氯鎓时,甲苯、乙腈做溶剂和无溶剂条件对产品收率的影响,认为溶剂极性较大和反应温度较高时更有利于反应的进行;同时,首次采用微波辐照法合成了1,3-双(3-三乙氧基硅丙基)-咪唑氯鎓,并考察了微波辐照功率、时间、投料比等对产品收率的影响;与常规合成方法相比,微波辐照合成1,3-双(3-三乙氧基硅丙基)-咪唑氯鎓具有反应时间短、收率高、不需要有机溶剂和操作方便等优点。该研究为快速、高效合成1,3-双(3-三乙氧基硅丙基)-咪唑氯鎓提供了新方法,为其他类似双硅烷化的有机硅前体的合成提供了新思路。     

11-甲苯基-2,3,4,5,10,11-六氢二苯并[b,e][1,4]二氮杂卓-1-酮的合成

以4-甲基苯甲醛、邻苯二胺和1,3-环二酮为原料,水为溶剂,在微波作用下,合成11-甲苯基-2,3,4,5,10,11-六氢二苯并[b,e][1,4]二氮杂卓-1-酮。通过正交实验确定较佳的合成条件为:反应温度为120℃,微波功率为125 W,反应时间为20 min,n(邻苯二胺):n(1,3-环己二酮):n(4-甲基苯甲醛)为1:1:1,该方法避免了有毒原料和大量有机溶剂的使用,操作简单,减少了有毒化合物的排放。     

正离子聚合制备异丁烯-对甲基苯乙烯无规共聚物及其溴化反应

通过正离子聚合法制备了异丁烯-对甲基苯乙烯无规共聚物,考察了单体浓度、聚合温度以及聚合时间对正离子聚合的影响,并通过光照溴化反应对共聚物进行溴化改性,制备出主链结构完全饱和的溴化异丁烯-对甲基苯乙烯无规共聚物(BIMS),对其结构与性能进行了表征。结果表明,在-80℃、单体质量分数为25%～28%时,异丁烯与对甲基苯乙烯正离子共聚合,聚合物的数均分子量可达2.1×10~5。随着温度的降低,聚合物的数均分子量增大,分子量分布变窄。随着溴含量的增加,BMIS中苄基溴含量也增加,当溴质量分数为1.9%时,聚合物中苄基溴摩尔分数达到1.38%。BIMS热稳定性较好,在较低的温度下仍能保持橡胶的高弹性,且耐热氧老化性能优异。     

微波辐射二苯甲酰甲烷烷基化反应的研究

苯甲酸乙酯和苯乙酮经克莱森缩合反应制得二苯甲酰甲烷。在相转移催化剂聚乙二醇的存在下,以固体氢氧化钾为碱性试剂,二苯甲酰甲烷与卤代烷在丙酮中,用微波辐射法进行烷基化反应。合成了两种不同的α-C单取代烷基产物,即:2-甲基-1,3-二苯基-1,3-丙二酮和2-乙基-1,3-二苯基-1,3-丙二酮,产率分别是82.6%和62.9%。产品结构经IR、MS和元素分析确证。     

Non‐catalyst synthesis and in vitro drug release property of poly(5,5‐dimethyl‐1,3‐dioxan‐2‐one)‐block‐methoxy poly(ethylene glycol) copolymers

A series of poly(5,5‐dimethyl‐1,3‐dioxan‐2‐one)‐block‐methoxy poly(ethylene glycol) (PDTC‐b‐mPEG) copolymers were synthesized by the ring‐opening polymerization of 5,5‐dimethyl‐1,3‐dioxan‐2‐one (DTC) in bulk, using methoxy poly(ethylene glycol) (mPEG) as initiator without adding any catalysts. The resulting copolymers were characterized by Fourier transform infrared spectra, ¹H NMR and gel permeation chromatography. The influences of some factors such as the DTC/mPEG molar feed ratio, reaction time and reaction temperature on the copolymerization were investigated. The experimental results showed that mPEG could effectively initiate the ring‐opening polymerization of DTC in the absence of catalyst, and that the copolymerization conditions had a significant effect on the molecular weight of PDTC‐b‐mPEG copolymer. In vitro drug release study demonstrated that the amount of indomethacin released from PDTC‐b‐mPEG copolymer decreased with increase in the DTC content in the copolymer. © 2013 Society of Chemical Industry     

环戊二烯阳离子聚合的研究--聚合反应条件对产物分子量的影响

随着石油化工和煤化工的迅速发展，环戊二烯的产量大幅度增加，其聚合物已用于聚丙烯等通用塑料的改性，赋予其热封性、气体阻隔性。本实验以TiCl4为引发剂，研究不同浓度、温度溶剂中引发环戊二烯的阳离子聚合。结果表明，溶剂对产物的分子量和分子量分布的影响最为显著，这与离子对的状态有密切的关系；并且用甲苯作溶剂时，^1HNMR结果表明甲苯作为聚合反应的链转移剂参与链转移反应。     

Preparation and Characterization of Poly(2,2-dimethyl-1,3-propylene oxalate) Polymer and the Study of its Metal Uptake Behavior Toward Pb(II), Cd(II), and Hg(II) Ions

Abstract

Poly(2,2-dimethyl-1,3-propylene oxalate) was synthesized from oxalyl chloride and 2,2-dimethyl-1,3-propane diol. The polymer was characterized by inherent viscosity, FT-IR, XRD, SEM, ¹H-NMR, ¹³C-NMR, DSC, and TGA. The polymer uptake behavior towards Pb(II), Cd(II), and Hg(II) ions was studied by the batch equilibrium technique as a function of pH and contact time. The adsorption isotherms of metal ions were also investigated. Column experiments were used to determine the loading capacity and study desorption of metal ions. The polymer showed high metal-ion uptake capacity towards Pb(II), but moderate capacity towards Cd(II) and Hg(II) ions. Interestingly, the polymer was found to be highly selective for Pb(II) ions at pH 5 and 25°C. The metal ion uptake properties of the polymer show fittings for both Langmuir's and Freundlich equations. The metal-bound polymer was regenerated by treatment with 1 M HNO₃. Therefore, it may be employed for the removal of heavy metal pollutants in environmental and industrial applications.     

Living non-conjugated polyacetylenes

Summary The non-conjugated poly (3,3-dimethyl-1-butyne) and poly (1-trimethylsilyl)-1-propyne were prepared by metathesis catalysts and the polymerization was monitored for molecular weight by GPC and monomer conversion by GC. Both the 1-(trimethylsilyl)-1-propyne and 3,3-dimethyl-1-butyne gave a linear relationship with number average molecular weight versus conversion and number average molecular weight versus monomer to initiator ratio. The 1-(trimethylsilyl)-1-propyne failed to polymerize beyond 100% conversion. The 3,3-dimethyl-1-butyne, however, gave conversion to 300%, with GPC data clearly showing the continuation of propagation from the living polymer chain. The living character of these polymerizations seems to be the result of both the lack of backbiting which can occur only from a cis-cisoidal growing chain, and the lack of interchain reactions. Both the cis-cisoidal configuration and the interchain reactions are prohibited for steric reasons.     

乙酸乙烯酯的微波加热聚合

对乙酸乙烯酯甲醇溶液在微波加热条件下的聚合反应进行了研究,讨论了微波聚合条件、引发剂浓度、溶剂浓度和种类对聚合产物的转化率和分子量的影响。聚合物可以在较短时间内获得。且在同样的实验条件下,用不同的溶剂获得的聚合物的分子量不同。     

Evolution to similarity solutions for polymerization and depolymerization with microwave radiation

The kinetics of polymerization and depolymerization are critical in understanding the stability and characterization of polymers. The kinetics of simultaneous polymerization and degradation of poly(methyl methacrylate) have been investigated by varying the initiator concentration and monomer concentration under the influence of microwave energy. Microwave radiation initially polymerizes the monomer, then degrades the resulting polymer and the polymer attains an equilibrium molecular weight distribution with a polydispersity of two. To understand more fully the kinetics, the molecular weight distribution (MWD) is represented as a gamma distribution; the random degradation rate coefficient is assumed to vary linearly with molecular weight and the polymerization rate coefficient is assumed to be independent of molecular weight. The change of the MWD with time is studied by continuous distribution kinetics; the solutions obtained depict the change of the average molecular weight, polydispersity and the gamma distribution parameters with time. Experimental data indicate that reaction rates are enhanced by microwave radiation and the MWD approaches a similarity solution within 10 min for all the investigated cases. The model satisfactorily predicts the change of the MWD with time. © 2001 Society of Chemical Industry     

Delocalized carbanions: synthesis and polymerization of 2,3-disubstituted-1,3-butadienes

Summary The 2,3-dimethylene-1,3-butadiene dianion (2) was prepared from 2,3-dimethyl-1,3-butadiene (1) using Lochmann's base (n-BuLi/potassium-t-butoxide in pentane). The dianion was reacted with primary halides to yield 2,3-disubstituted-1,3-butadiene monomers. These monomers were polymerized free radically with AIBN and with Ziegler/Natta coordination catalysts. The resulting polymers were examined by DSC for crystallization of the polymer backbone and alkyl side chains.     

Photodegradation of poly(2,6-dimethyl-1,4-phenylene oxide) film with metal isopropylxanthates

The effect of metal (Co and Zn) isopropylxanthates over the range of 0.3 to 2.5% (w/w) on the photodegradation of poly(2,6-dimethyl-1,4-phenylene oxide) film was examined, by changes in the carbonyl i.r. absorption, hydroperoxide, weight average molecular weight and quantum yield of the polymer samples. The data have been processed to yield the heats of activation of the system. The photodegradation of the polymer was affected by the kind of metal, concentration of the xanthates, wavelength of irradiated light, and by the temperature. Zinc isopropylxanthate was found as a photostabilizer whereas cobalt isopropylxanthate merely enhanced the degradation. The presence of metal xanthates changed the u.v. spectra of the polymer.     

Determination of molecular weight and size distribution and branching characteristics of PVAc by means of size exclusion chromatography/multi-angle laser light scattering (SEC/MALLS)

SEC/MALLS has been applied for the determination of molecular weight and size distributions and to quantify branching in polyvinyl acetate (PVAc). Linear and branched samples obtained by solution and bulk polymerization were analyzed. The molecular weight distribution of the branched polymer was broader and the mean square radius was found to be smaller, 38.8 nm (with molecular weight of 770?000), than for the linear polymer, 42.3 nm (with molecular weight of 740?000). Branching characteristics could be determined by using Zimm and Stockmayer equations. It has been found that the number of branches for the branched sample increases from about 1 to 9, per molecule, with increasing molecular weight.     

Crystallization of dilute polyethylene solutions: influence of molecular weight

The crystallization kinetics of linear polyethylene over the molecular weight range 14 000–1 200 000 was studied in dilute solutions of α-chloronaphthalene by dilatometric techniques. The experimental results could be quantitatively described by the Avrami and Göler-Sachs theories for a significant part of the transformation. The influence of molecular weight on the time necessary for 10% of crystallinity to develop was also analysed and the obtained curves follow the same pattern as in the bulk. The temperature coefficient of crystallization was studied by using the two-dimensional nucleation theory and it was found that the basic interfacial free energy is about four times lower than the value reported previously for the pure polymer.