Synthesis,characterization of potassium bulky phenolate and application in ring-opening polymerization of L-lactide

The reaction of 2,2′-ethylidenebis(4,6-di-tert-butylphenol) (EDBP-H₂) with potassium gives [EDBPH·K·(THF)₂] (1) in 92% yield. Experimental results show that potassium complex 1 is an efficient catalyst for the ring-opening polymerization of lactide in controlled fashion, yielding polymers with expectative molecular weight and low polydispersity indexes. Furthermore, the complex 1 has isotactic selectivity for the ring-opening polymerization of rac-lactide.     

Synthesis and characterization of controlled benzotriazole light stabilizer by RAFT polymerization and its application

A polymerizable benzotriazole light stabilizer 2-(2’-Propionyloxy-5′-methylphenyl) benzotriazole (AMB) was synthesized, which was copolymerized with styrene to prepare poly(St-co-AMB) by reversible addition fragmentation chain transfer (RAFT) polymerization. The Fourier transformed infrared (FTIR) and nuclear magnetic resonance analysis showed that AMB monomer and poly(St-co-AMB) were successfully prepared. The results showed that AMB had been effectively added to the polymer chain and poly(St-co-AMB) with different molecular weight and narrow distribution can be obtained under suitable conditions. The thermogravimetry analysis (TGA) results showed that poly(St-co-AMB) had good heat resistance. Moreover, the tensile strength and notched impact strength of PP/poly(St-co-AMB) was significantly improved, respectively after 600 h UV irradiation, which were both much higher than that of pure polypropylene (PP). In addition, poly(St-co-AMB) was much better than general commercial light stabilizer UV-P in the resistance to extraction.     

Synthesis,characterization and polymerization of waxy monomers

Waxy monomers and crosslinkers, respectively, were synthesized from commercially available waxes by esterification with 2-hydroxyethyl methacrylate, glycerol dimethacrylate, or glycidyl methacrylate or by functionalization with 2-isocyanatoethyl methacrylate. The resulting opaque methacrylates with melting points between 45 and 80°C were polymerized in bulk and in toluene solution in presence of free radical initiators. The obtained polymers were characterized by a broad molecular weight distribution. Opposite to the bulk polymerization, the double bond conversion in solution polymerization is nearly quantitative. The observed volume shrinkage during polymerization is very low due to the high molecular weight of the monomers. Polymerizates containing crosslinking comonomers exhibit improved mechanical stability.     

Synthesis and characterization of cross-type vinylurethane macromonomer (C-VUM) and their application in the dispersion polymerization of styrene

The cross-type vinylurethane macromonomers (C-VUMs) were successfully synthesized using trimethylolpropane (TMP) as a cross-agent, and applied to the dispersion polymerization of styrene in ethanol. The existence and the structural identification of the reactants and the products were verified using the FT-IR and ¹H NMR spectra. The molecular weight of C-VUM increased, but the polydispersity index of C-VUM decreased with that of PEG. Structural verification of PS spheres synthesized from C-VUMs is carried out using ¹H NMR. However, the molecular weight of polyethylene glycol (PEG) in C-VUM does not affect the particle size of the PS particles, whereas enhanced the uniformity of the PS particles. Thus, C-VUMs act not only as reactive stabilizers, but also as grafting agents     

Synthesis and characterization of fluoropolymer modified polyacrylate in emulsion polymerization

A novel method to produce fluorine‐containing polyacrylate emulsion is presented. It is prepared by the copolymerization of n‐methyl methacrylate, n‐styrene, n‐butyl acrylate, and α‐methacrylic acid in the presence of swollen particles of PTFE. The structure and properties of the polymers are characterized by GPC, PSD, SEM, and XPS. The number‐average molar mass (Mn) 51,332, and the polydispersity 5.8688 are obtained. The mean diameter of latex particles is 300nm. Scanning electron microscopy reveals that particles of the emulsion are well dispersed. Meanwhile, the F_1S content of the surface on the latex membrane is 8.99%. It is shown that the method of mixing micron and nanometer‐sized particles should be made the next step of research. It is also proved that inertia polymers can be used in emulsion property modification. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 558–562, 2006     

铁系聚烯烃催化剂的合成及其应用

合成了2类铁系聚烯烃催化剂(常规铁系催化剂及树枝状铁系催化剂).评价了这两类催化剂在丙烯聚合中的催化效果.结果表明:在温度20℃、n(Al)/n(Fe)为1 000时,常规铁系催化剂的催化活性为137 kg,(mol·h),楔形树枝状铁系催化剂聚合活性为163 kg/(mol·h),聚合物的数均分子量也提高到1×104以上,等规指数约为76%.     

Synthesis and characterization of PS-clay nanocomposite by emulsion polymerization

Summary Polystyrene-Na⁺-montmorillonite(PS-Na⁺-MMT) nanocomposites are prepared by a simple emulsion polymerization. The X-ray diffraction(XRD) and infrared spectroscopy (IR) analysis confirm that polystyrene(PS) macromolecules can be inserted between lamella layers and whose layer separation is consequently higher than in the polymer-free clay. The enhanced thermal properties of composites are measured by differential scanning calorimetry(DSC) and thermogravimetric analysis(TGA) thermogram and indicate that the glass transition and the decomposition onset temperature of obtained nanocomposites are found to be moved to the higher temperature region. The increased Young's modulus of the obtained nanocomposites is ascribed to the intercalation of PS in clay galleries as well as the fine dispersion of clay particles into the polymer matrix. Received: 23 February 1999/Revised version: 26 March 1999/Accepted: 1 April 1999     

结晶Ⅱ型高聚合度聚磷酸铵的合成及表征

研究在高压条件下以磷酸-铵和缩合剂三聚氰胺为原料生产聚磷酸铵（APP）的合成工艺条件,制备了平均聚合度为580的聚磷酸铵（APP—Ⅱ）。结果表明,n（三聚氰胺）抗（磷酸-铵）=1、反应温度280℃、反应时间90min、反应压力100MPa、热处理温度250℃、热处理时间120min、湿氨气反应气氛为制备结晶Ⅱ型高聚合度的聚磷酸铵阻燃剂的最佳工艺条件。合成的产品通过IR、XRD分析与商业APP—Ⅱ进行了对比,两者在结构与晶型上一致。     

反应型乳化剂的合成及其在乳液聚合中的应用

合成了2类可聚合乳化剂马来酸酐单酯硫酸钠和马来酸酐单酯磺酸钠，测定了产物的纯度和临界胶束浓度，研究了它们在苯乙烯/丙烯酸丁酯/丙烯酸三元乳液聚合中的转化率。以十二烷基硫酸钠为参照物，用可聚合乳化剂制备的乳液对电解质的稳定性有很大的提高，干胶膜的耐水性和拉伸强度得到了显著改善。     

A novel rare earth coordination catalyst for polymerization of biodegradable aliphatic lactones and lactides

A novel rare earth coordination system composed of lanthanide trifluoroacetates Ln(CF₃COO)₃ (Ln=Y, Yb, Nd, Tm, Ho, La, Pr) and tri-isobutylaluminium Al(i-Bu)₃ was used as catalyst for the polymerization of ε-caprolactone (CL), D ,L -lactide (DLLA) and their copolymerization. The influence of temperature, time and catalyst concentration on polymerization yields and molecular weights of the polyesters have been studied. It was shown that the ring-opening polymerization of cyclic esters catalysed by Ln(CF₃COO)₃/Al(i-Bu)₃ has some living character and the molecular weight of the polyester could be controlled by adjusting the molar ratio of monomer to catalyst. The DLLA/CL copolymer was synthesized by sequential addition of monomers and the structure of the copolyester was characterized by GPC, NMR and DSC. © 1998 SCI.     

Synthesis and characterization of telechelic polymers obtained by micellar polymerization

Summary The synthesis, characterization and rheological properties in aqueous solution of two telechelic polymers of different structures and size are reported: they are water soluble polyacrylamides, hydrophobically modified with linear and di-substituted hydrophobic initiators. The polymers were prepared via free radical micellar polymerization. The results of static light scattering (SLS), showed similar weight-average molecular weights (M_w) in all of the synthesized polymers. No signal corresponding to the presence of the hydrophobic group of the initiator could be observed by ¹H NMR; however, the presence of these hydrophobic groups was demonstrated using rheological measurements.     

直接熔融聚合聚乙醇酸的合成与表征

以乙醇酸为原料,在催化剂氯化亚锡质量分数0.5％,反应温度165℃,反应压力70 Pa,反应时间10 h的条件下进行熔融聚合,直接合成了生物降解的医用纤维材料聚乙醇酸(PGA),用IR,DSC,X射线衍射等进行了表征,并与乙交酯开环聚合二步法合成PGA进行了比较。直接熔融聚合PGA的结晶度和微晶尺寸高于二步法,其合成工艺流程短、简单易行、耗时少,有利于降低医用纤维材料PGA的开发成本。     

Synthesis and characterization of ethylene-xylene-based polysulfide block-copolymers using the interfacial polymerization method

Copolymers of linear and aromatic polysulfide blocks are synthesized using interfacial polymerization of dichloro-xylene-based aromatic and ethylene-dichloride-based non-aromatic organic monomers. Synthesized copolymers consist of poly(ethylene sulfide) as well as ploy (xylene sulfide) blocks. Fascinating properties of linear and aromatic polysulfide species are gathered in the structure of synthesized polysulfide copolymers. Ethylene dichloride and α,α′-dichloro-p-xylene are used as the non-aromatic and aromatic organic monomers, respectively. To investigate the influences of sulfur contents in the backbone of the polymer on the thermal stability of synthesized copolymers, poly(ethylene-xylene disulfide) (PEXDS), poly(ethylene-xylene trisulfide) (PEXTRS) and poly(ethylene-xylene tetrasulfide) (PEXTS) copolymers are synthesized using, respectively, sodium disulfide, sodium trisulfide and sodium tetrasulfide, as aqueous monomers. Compared to both linear and nonlinear homopolymers, synthesized copolymers exhibit improved thermal stability. Moreover, the thermal degradation temperatures of synthesized copolymers improve by decreasing the number of sulfur atoms in the backbone of copolymers. These results reveal that thermal degradation of polysulfide copolymers can be tailored by controlling the polysulfide chain’s sulfur contents. Structural characteristics of synthesized polysulfide copolymers are also investigated using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy and X-ray diffraction analysis.     

Inverse suspension polymerization of sodium acrylate: Synthesis and characterization

Crosslinked Poly(acrylic acid) was synthesized by inverse suspension polymerization. This process was investigated to determine the influence of different parameters like temperature, stirring speed, solution pH, and crosslinker concentration and to obtain the best control of the kinetics. An aqueous phase containing partially neutralized acrylic acid, crosslinking agent, and initiator agent was dispersed in an organic phase and stabilized by a surfactant. The inverse suspension was carried out in heptane as the organic phase with a different ratio of neutralization of the monomer, different crosslinker concentrations, and several stirring speeds. The polymerization was initiated by potassium persulfate (K₂S₂O₈) with N‐N′‐methylenebisacrylamide (MBA_C) as the crosslinker and sorbitan monooleate as the surfactant. The influence of several parameters on the bead size and the swelling capacity was investigated. Particle diameters ranged from 10 to 130 μm. The kinetic results obtained by differential scanning calorimetry showed that conversion and polymerization rates are a function of the solution pH, and they fell when the concentration of the crosslinking agent was higher than 7.5% in the mass of MBA_C. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2621–2630, 2000     

反应性乳化剂的制备及其在纯丙乳液聚合中的应用

将马来酸酐分别与苯甲醇、正辛醇、十二醇、十四醇和脂肪醇聚氧乙烯醚AEO-7通过酯化、中和反应生成相应的产物,依次记为ME-B,ME-8,ME-12,ME-14和M-AEO-7,测试并对比了各产物乳化力和临界胶束浓度的大小。结果表明ME-12和M-AEO-7的综合性能较佳。采用红外光谱对2者的结构进行表征。分别将十二烷基硫酸钠SDS、ME-12和M-AEO-7用于纯丙乳液聚合中,发现采用自制的反应性乳化剂所得乳液的聚合稳定性和乳胶膜的耐水性比SDS有所提高。将ME-12分别和AEO-3(AEO-5或AEO-7)以1∶1或1∶1.5质量比复配使用,仅在m∶m=1∶1.5时乳液的耐电解质稳定性才较好,而ME-12 AEO-7单独采用M-AEO-7即能得到耐电解质性能极佳的聚合物乳液。     

Synthesis and characterization of polyurethane/montmorillonite nanocomposites by in situ polymerization

In this paper, a new type of organophilic montmorillonite, co‐treated with cetyltrimethyl ammonium bromide (CTAB) and 4,4′‐diphenymethylate diisocyanate (MDI), was modified and applied to prepare polyurethane/montmorillonite nanocomposites via in situ polymerization. The nanoscale montmorillonite layers were exfoliated and dispersed relatively homogeneously in the polyurethane matrix, and characterized by X‐ray diffraction and transmission electron microscopy. The thermal degradation temperature of the nanocomposites increased, as compared with pristine polyurethane. Dynamic mechanical analysis confirmed the constraining effect of exfoliated montmorillonite layers on polyurethane chains, which benefited the increased storage modulus and increased glass transition temperature. Tensile tests showed that the exfoliated nanocomposites were reinforced and toughened by the addition of nanometer‐size montmorillonite layers. Copyright © 2006 Society of Chemical Industry     

Synthesis and characterization of homo- and copolyimides prepared from two-step polymerization

Homopolyamic acids and copolyamic acids were prepared from four dianhydrides and three diamines. Copolyimides could be arranged in sequence through different reaction processes, such as alternating, block, and random. Polyamic acids were subsequently converted into corresponding polyimides by the solid-phase imidization. Polyimide derivatives were characterized by viscosity, thermal stability, mechanical properties, and solubility. The extent of polymerization might be influenced by the nucleophilicity of a diamine and the electrophilicity of a dianhydride. In gel permeation chromatography, molecular weight distribution of polymers was 2.5–3.0. The thermal stability of polymers decreased with increasing the ratio of a more flexible component, and alternating copolyimides showed slightly better than corresponding random and block ones. The melting temperatures of all polyimide derivatives did not exist on the differential scanning calorimetry curves, and the results were proof that the X-ray diffraction curves. Polymers derived from bis[4-(3-amino phenoxy)phenyl]sulfone dissolved well in some polar solvents. Alternating copolymers represented a better solubility than the corresponding random and block ones. All polymers had good mechanical properties, both tensile and elongation. The kinetics of imide formation could be also dependent on the structure and reactivity of reagents. The kinetics of cyclo-dehydration was described by the first-order kinetics up to relatively high conversion but deviated from the first-order kinetics at high conversion followed by the second-order kinetics. © 1996 John Wiley & Sons, Inc.     

高聚合度聚磷酸铵的合成及表征

在常压下合成了高聚合度聚磷酸铵,并对其结构与性能进行了表征。其优化配方为：n（五氧化二磷）∶ n（磷酸氢二铵）∶n（尿素）∶n（三聚氰胺）为1∶1∶0.3∶（0.02～0.14）,反应时间为300 min,温度为290 ℃。X射线衍射和红外光谱表征结果表明,所合成的产物为Ⅱ型聚磷酸铵;粘度法测定该产品平均聚合度与德国科莱恩无卤阻燃剂Exolit 422 聚磷酸铵比较接近;五氧化二磷的质量分数为74.88%;在水中的溶解度仅0.455 g（以100 g水计）;热重分析结果表明该产物的初始分解温度与Exolit 422 聚磷酸铵接近。     

新型树枝状镍系催化剂的合成、表征及催化乙烯聚合的性能

合成了一种含有强供电子、较大空间位阻的新型树枝状水杨醛亚胺配体及其镍配合物,利用1H NMR、元素分析、FT-IR、UV进行了表征。以配合物为催化剂,甲基铝氧烷（MAO）为助催化剂对乙烯齐聚反应进行了研究,详细考察了聚合反应温度、Al/Ni摩尔比、反应压力及时间对催化剂活性及产物分布的影响。结果表明,齐聚产物为不同碳链的烯烃,在温度为25℃、Al/Ni=500、压力为0.5MPa、时间为0.5h的条件下,树枝状催化剂的活性最高,达到4.93?105g/(mol Ni?h),C10～C18的含量为54.17%。     

Synthesis and characterization of fluorene end-labeled polymers prepared by nitroxide-mediated polymerization

The fluorene-based alkoxyamine 9-(2,2,6,6-tetramethyl-4-hydroxypiperidinyloxy)fluorene was prepared and investigated as a unimolecular initiator in the nitroxide-mediated polymerization (NMP) of styrene. Reactions performed in either bulk or ethereal solvents at 125 °C generated polymers possessing low polydispersity indices (PDIs) and number average molecular weight (M_n) values close to those anticipated based on monomer-to-initiator ratios. A linear relationship between monomer conversion and M_n values was observed by analysis of reaction aliquots with ¹H NMR and gel permeation chromatography (GPC), while PDI values remained low throughout. Analysis of the polymers by UV–vis spectroscopy indicated that approximately 80% of the polymer chains were labeled with the fluorene chromophore, while fluorescence spectroscopy was used to verify that the fluorene was polymer-bound.