Synthesis of mid-dicarboxy polystyrene by ATRP and formation of ionic-bonded supramolecules

Dimethyl 4,6-bis(bromomethyl) isophthalate was synthesized by bromomethylation, oxidation, esterification and bromination of 1,3-dimethylbenzene. This was used to initiate the atom transfer radical polymerization of styrene successfully. Results showed that the process had some of the good characteristics of controlled/living free radical polymerization. The molecular weight of the obtained polymer increased linearly with monomer conversion, its molecular weight distribution was very narrow, and a linear relationship between ln([M]₀/[M]) and polymerization time was found. A well-defined novel structural polystyrene containing two ester groups in the mid-main chain was prepared with controlled molecular weight and narrow polydispersity. The structure of the polymer was confirmed by ¹H-NMR spectra. After being hydrolyzed, dicarboxy polystyrene was obtained and used to form ionic-bonded supramolecules with 1-dodecanamine as a model of the star-shaped supramolecules. The supramolecules formed were characterized by Fourier transform infrared (FTIR) spectrum. Translated from Acta Polymerica Sinica, 2006, (4): 597–602 [译自: 高分子学报]     

Synthesis and characterization of a novel liquid crystalline star‐shaped polymer based on α‐CD core via ATRP

Well‐defined side‐chain liquid crystalline star‐shaped polymers were synthesized with a combination of the “core‐first” method and atom transfer radical polymerization (ATRP). Firstly, the functionalized macroinitiator based on the α‐Cyclodextrins (α‐CD) bearing functional bromide groups was synthesized, confirmed by ¹H‐NMR, MALDI‐TOF, and FTIR analysis. Secondly, the side‐chain liquid crystalline arms poly[6‐(4‐methoxy‐4‐oxy‐azobenzene) hexyl methacrylate] (PMMAzo) were prepared by ATRP. The characterization of the star polymers were performed with ¹H‐NMR, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and thermal polarized optical microscopy (POM). It was found that the liquid crystalline behavior of the star polymer α‐CD‐PMMAzo_n was similar to that of the linear homopolymer. The phase‐transition temperatures from the smectic to nematic phase and from the nematic to isotropic phase increased as the molecular weight increased for most of these samples. All star‐shaped polymers show photoresponsive isomerization under the irradiation with Ultraviolet light. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of side-chain liquid-crystalline block-copolymers containing laterally attached photoluminescent quinquephenyl units via ATRP

A series of novel side-chain liquid-crystalline polymers (SCLCPs) consisting of laterally attached photoluminescent p-quinquephenyl (QQP) pendants with different flexible terminal- and/or side-alkoxy chains were synthesized via atom transfer radical polymerization (ATRP). Homopolymers (HP1-HP3) and block-copolymers (PSP1-PSP3 and PEOP1-PEOP3), where QQP units were copolymerized with styrene or ethylene oxide monomers, possessed the number average molecular weights (M_n) of 8.7-26.0 × 10³ with narrow PDI values of 1.08-1.26. Various characterization techniques of polarized optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) were used to investigate their mesomorphic properties, and all homopolymers and block-copolymers exhibited the nematic phase affected by the flexible terminal- and/or side-alkoxy chains of the conjugated rod-like pendants. In addition, the photophysical properties of these polymers were measured by UV-vis and photoluminescence (PL) spectroscopies, which showed blue PL emissions with rather high fluorescence quantum yields in solutions.     

Synthesis of cyclic polystyrene via a combination of intramolecular coupling and ATRP

Cyclic polystyrene with narrow molecular weight distribution was synthesized by intramolecular coupling of α-carboxyl-ω-butylamino heterotelechelic polystyrene using 2-chloro-1-methylpyridinium and triethylamine as the catalyst in highly dilute solution. The linear precursor α-carboxyl-ω-butylamine polystyrene was first prepared by atom transfer radical polymerization using 4-(chloromethyl)benzoic acid as the initiator and followed by nucleophilic substituted with n-butylamine. The results of IR, ¹H NMR, and gel permeation chromatography revealed that highly pure cyclic polystyrene was synthesized via a combination of intramolecular coupling and atom transfer radical polymerization, and can be isolated easily by column chromatography on silica gel using ethyl acetate as the eluant.     

Synthesis and properties of novel macromolecular coupling agents prepared by ATRP

Novel block and graft macromolecular coupling agents with well‐defined structures have been synthesized successfully by atom transfer radical polymerization (ATRP). The molecular weights and molecular weight distributions of those functional copolymers can be controlled because of the living/controlled ATRP. The structures and composition of block and graft copolymers with the monomers of butyl acrylate (BA), styrene (St), and 3‐methacryloxyl‐propyltrimethoxyl silicon (KH‐570) have been characterized by mean of ¹H NMR, IR, GPC, and UV. Because the KH‐570 of macromolecular coupling agents owns strong affinity to surface hydroxyl of fillers, inorganic fillers that were treated by the macromolecular coupling agents possess some new properties, for example increasing the effect between matrix and fillers of composites. The mechanical properties and morphology of composites with macromolecular coupling agents have been investigated by the dynamic mechanical spectra and SEM. The results showed that the damping value and compatibility of composites with macromolecular coupling agents were improved greatly when compared with that of composite with small molecular coupling agent. Furthermore with different contents of BA, St, and KH‐570 in the macromolecular coupling agents, the damping value of the composites are different. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3919–3926, 2006     

Synthesis and characterization of benzoylated syndiotactic polystyrene

Benzoylated syndiotactic polystyrene, a functional polymer bearing benzophenone(BP) moiety, has been synthesized in a heterogeneous process by using carbon disulfide as the dispersing medium, and benzoyl chloride and anhydrous aluminum chloride as benzoylating agent and catalyst, respectively. The benzoylation reaction can be well controlled and the resultant polymer was characterized by FTIR and NMR spectroscopy. The incorporation of benzoyl groups into syndiotactic polystyrene was found to have a profound effect on the thermal properties of these new materials. The melting point and the degree of crystallinity decreased by the presence of benzoyl groups, while the glass transition temperature increased.     

Synthesis, characterization and use of reactive polymers with diisopropylphenylphosphine groups

The synthesis of linear and crosslinked polymers starting with 4-(diisopropyl-phosphinyl) styrene is described. Treatment with triphosgene yields the corresponding phosphine dichloride group in the polymers. Using these reactive polymers benzyl alcohol was converted to benzyl chloride at room temperature. The regeneration of the reactive polymers using triphosgene was achieved. The yields of benzyl chloride were in general lower than those previously reported using triphenylphosphine dichloride groups in the polymers. The difference in reactivity between triphenylphosphine dichloride- and diisopropylphenylphosphine dichloride substituted-polymers are discussed with the aid of semi-empirical computer calculations. Received: 17 June 1997/Revised: 4 September 1997/Accepted: 9 September 1997     

Synthesis of polystyrene microgel with glucose as hydrophilic segment via controlled free-radical polymerization

4-Vinylbenzyl glucoside peracetate (1) was copolymerized with divinylbenzene (DVB) using 1-phenyl-1-(2′,2′,6′,6′-tetramethyl-1′-piperidinyloxy)ethane (2) as an initiator in m-xylene at 138 °C for 20 h ([DVB]/[2]=28; [DVB]=0.62 mol L⁻¹). The copolymerizations were performed using the mole fraction of 1 in the total feed of 1 and DVB (F₁: [1]/[1]+[DVB]) ranging from 0.11 to 0.38 that produced the polystyrene (PSt) microgel with acetyl glucose, 3, in 46-53% yields. Dynamic laser light scattering (DLS) measurements showed that 3 was stably suspended in toluene as particles with average diameters (d's) ranging from 12 to 22 nm. A static laser light scattering (SLS) measurement gave the average molar mass, M_w,SLS, of 3 that ranged from 9.69×10⁴ to 6.96×10⁵. The numbers of the 1, 2, and DVB units in 3 (N₁, N₂, and N_DVB, respectively) were from 111 to 238, from 17 to 208, and from 350 to 4510, respectively. The deacetylation of 3 was achieved by treatment with sodium methoxide in dry 1,4-dioxane to produce the PSt microgel with glucose as the hydrophilic segment, 4. The solubilities of 4 in toluene, CHCl₃, THF, 1,4-dioxane, pyridine, DMF, DMSO, and H₂O, and the mixture of H₂O and 1,4-dioxane were examined, indicating that a hydrophilic property had been effectively introduced into 4.     

氢化钠/三异丁基铝体系合成星形聚苯乙烯的研究

采用阻滞阴离子调控技术,通过"先核后臂"法以NaH/三异丁基铝(i-Bu3Al)与苯乙烯、二乙烯基苯(DVB)反应制备的多钠引发剂为核,乙苯为溶剂,合成了星形聚苯乙烯(PS)(cs-PS);通过"先臂后核"法,以NaH/i-Bu3Al直接引发苯乙烯聚合,DVB为偶联剂,也合成了星形聚苯乙烯(as-PS)。采用气相色谱测定了聚苯乙烯钠与DVB中四种组分在100℃下的聚合反应速率,并用凝胶渗透色谱分析测试了聚合物的分子参数及平均臂数。结果表明:聚苯乙烯钠与DVB中四种组分的聚合反应速率与单体浓度呈假一级动力学关系;随着n(DVB)/n(NaH)的增加,cs-PS和as-PS的相对分子质量均逐渐增加,相对分子量分布均变宽,平均臂数也随之增大。     

Well-defined core-shell structures based on silsesquioxane microgels: Grafting of polystyrene via ATRP and product characterization

Silsesquioxane microgel nanoparticles characterized by low diameters (below 30 nm) and reduced polydispersity can be produced in an acid-catalyzed sol-gel process in an aqueous microemulsion. Suitable surface modification of such structures leads to macroinitiators for atom-transfer radical polymerization (ATRP). This polymerization method was applied in order to graft polystyrene chains onto the surface of the microgels. Well-defined structures exhibiting a core-shell architecture were produced with the M_w of grafted polymers ranging from 8.5 to about 30 kg/mol. The products were extensively characterized with light scattering, X-ray scattering, thermal analysis (TGA/DSC) and microscopy (TEM/SEM) to obtain information on parameters characterizing polystyrene brush. Polymer-grafted nanoparticles will be used for the modification of homopolymer and block copolymer matrices.     

Macroporous crosslinked hydrophobic/hydrophilic polystyrene/polyamide interpenetrating polymer network: Synthesis,characterization, and adsorption behaviors for quercetin from aqueous solution

In the present study, a novel hydrophobic/hydrophilic polystyrene/polyamide interpenetrating polymer network (PS/PAM IPN) was synthesized and its molecular structure was characterized by Fourier transform infrared ray (FT‐IR) spectrum, chemical analysis, swelling test, and N₂ adsorption‐desorption experiment. The obtained PS/PAM IPN was employed as a polymeric adsorbent to adsorb quercetin from aqueous solution, and the adsorption thermodynamics were calculated according to thermodynamic equations. It was found that no chemical bond was formed between PS and PAM and PS/PAM IPN held characters of amphiphilic polymer network (APN). The adsorption isotherms could be well fitted by Freundlich isotherm, and the adsorption was shown to be an exothermic, spontaneous, and more ordered process. The total adsorption capacity from the column adsorption experiment was measured to be 8.6 mg/mL wet resin, and the adsorbed quercetin on PS/PAM IPN could be easily desorbed by 10% of hydrochloric acid‐ethanol. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis,characterization, and property of end-functionalized telechelic PST via ATRP

Polystyrene incorporating carboxylate group as α-end was synthesized by using initiator 4-chloromethyl benzoic acid via atom transfer radical polymerization. Its ω-chlorine end-group was transformed by cumic acid, diethyl malonate, and thiol, respectively, to form end-functionalized telechelic polystyrenes. These PSts with different functionalized ω-end group (PSt 1 , PSt 2 , and PSt 3) were obtained and characterized by H NMR and TGA. This type of end-functionalized telechelic polymers can further act as polymeric ligands to form polymeric metal complexes. In this study, PSt 1 with carboxylate group at each end was allowed to react with Eu(DBM)₂Cl·2H₂O to afford a new polymeric complex PSt 1 -Eu(III) showing significant red-light emission. Moreover, the film of PSt 1 -Eu shows similar emission pattern with its DMF solution. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of a novel POSS/PS composite via ATRP of branched functionalized POSS

A new process to prepare L-lactic acid based polymer with high molecular-weight was established. In this process, the carboxyl terminated poly (L-lactic acid) (PLLA) prepolymer was first synthesized via polycondensation of L-lactic acid and a little adipic acid, and then the molecular weight of PLLA was increased by a chain-extending reaction using bisphenol-A epoxy resin as a chain extender. In situ FTIR was used to characterize the activity of reaction between epoxy groups at the end of bisphenol-A epoxy resin and carboxyl groups at the end of PLLA prepolymer, and the results showed that the reaction was of high activity. The weight-average molecular weight of prepared L-lactic acid based copolymer (PLLA-co-BisA ER) was up to 210,000 at an optimum synthetic condition. The thermal property and crystallization behavior of prepared copolymer were also studied.     

表面接枝高密度磺酸基聚苯乙烯的制备及表征

以无水溴化铝为催化剂,对氯苯甲醛为醛基化试剂,通过傅克反应在聚苯乙烯微球表面接枝醛基;基于醛基的可氧化性,利用还原剂硝酸铵铈将树脂微球表面的醛基自由基化,引发对苯乙烯磺酸钠在树脂微球表面聚合,并对其进行表征。结果表明,聚苯乙烯微球磺酸化改性成功,优化的磺化工艺条件为:醛基含量1.5 mmol/g的聚苯乙烯微球用量0.3 g,对苯乙烯磺酸钠质量浓度40 g/L,硝酸铵铈质量浓度40 g/L,反应温度70℃,在此条件下制备的树脂表面磺酸基含量为58 mmol/g。     

对甲氧基偶氮苯星形聚合物的合成与表征

利用原子转移自由基聚合(ATRP)技术合成了对甲氧基偶氮苯星形聚合物。均苯三酚与2-溴异丁酰溴通过酯化反应得到三官能团引发剂,引发对甲氧基偶氮苯单体6-[4-(4-甲氧基苯基偶氮)酚氧基]己基甲基丙烯酸酯(MMAzo)的ATRP反应。表征了星形聚合物结构、热行为与液晶性,显示其与线性均聚物的液晶性相似,均显示近晶相和向列相,但其相转变温度有所降低。     

Synthesis and characterization of poly(methyl methacrylate) star polymers

Star-branched poly(methyl methacrylate)s (PMMA) were synthesized by linking ‘living’ arms (produced by anionic polymerzation) with ethylene glycol dimethacrylate. Stars having arm molecular weights of 10000 and 40000 and between 4.9 and 18.7 branches were produced. The polymers were characterized using light scattering, size exclusion chromatography, and viscometry. It was found that well-defined PMMA stars were obtained only at the higher (40000) arm molecular weight. The stars prepared using the lower molecular weight (c. 10000) arms contained very high molecular weight gel components.     

Synthesis of amphiphilic block copolymers via ARGET ATRP using an inexpensive ligand of PMDETA

Amphiphilic block copolymers, methoxy polyethylene glycol-b-poly(butyl methacrylate), were synthesized via activators regenerated by electron transfer for atom transfer radical polymerization(ARGET ATRP) of butyl methacrylate (BMA), where pentamethyldiethylene triamine (PMDETA) was utilized as the ligand. The results show that the minimum amount of the catalyst required in the ARGET ATRP of BMA with a high degree of control depends upon the molar ratio of [catalyst]₀/[initiator]₀. With PMDETA as the ligand and methoxy polyethylene glycol 2-bromo-iso-butyrate (MPEG-Br) as the macro-initiator, the ratio of [CuBr₂]₀/[MPEG-Br]₀ should be higher than 0.025:1. At this value, the copper catalyst level can be lowered to 50 ppm when the degree of polymerization of the BMA segment is set at 500. Reaction conditions that impact the controllability of the polymerization and the corresponding properties of the block copolymers were investigated.     

Factors controlling surface morphology of porous polystyrene membranes prepared by thermally induced phase separation

A special device for preparing porous polymer membranes through a thermally induced phase separation (TIPS) process was designed and machined; it included a solution container, a membrane‐forming platform, a coldplate, a temperature‐decreasing system and a temperature‐supervising system. Polystyrene was selected as the model polymer from which to prepare porous membranes using the device due to its better understood TIPS and good biocompatibility with cells. The major factors controlling surface morphology and cell size, ie volume fraction of polystyrene (ϕ₂), quench rate and solvent‐removing methods, were studied. Fixing the coldplate temperature, when ϕ₂ is as low as 0.045, provokes the formation of round pores on both the bottom and top surfaces of the membrane; when ϕ₂ = 0.16 no pores are formed on either surface; when ϕ₂ = 0.087 pores form on the top surface, but not on the bottom surface. When ϕ₂ = 0.087 the cell size is very small or no pores are formed on the bottom surface, whereas the top surface shows a regular decrease of the pore sizes and an increase of the pore number and pore area, along with a decrease of the coldplate temperature. The side near the coldplate is dense, and the dense layer aligns along the coldplate, while the side away from the coldplate is like a porous foam, the shape of which is isotropic and the surfaces are interconnected with each other three dimensionally. On the top surface of a membrane obtained by ethanol extraction, the cell size is enlarged and the cell number reduced, but the surface morphology and the whole area remained almost the same when compared to samples obtained by freeze drying in the same membrane‐forming conditions. The isotropic, uniformly distributed and round pores suggest that the mechanism of phase separation is a spinodal liquid–liquid decomposition under our research conditions. © 2000 Society of Chemical Industry     

Synthesis and characterization of cyclohexene oxide functional polystyrene macromonomers by ATRP and their use in photoinitiated cationic polymerization

In this study, a novel well-defined macromonomer of epoxy end-functionalized polystyrene was synthesized by atom transfer radical polymerization (ATRP). The compound 3-cyclohexenylmethyl-2-bromopropanoate was synthesized by the condensation of 3-cyclohexene-1-methanol with 2-bromopropanoyl bromide. Subsequently, the epoxidation of the obtained 3-cyclohexenylmethyl-2-bromopropanoate using 3-chloroperoxybenzoic acid results in a new epoxy functional ATRP initiator. The ATRP of styrene (St) in bulk at 110 °C, by means of this initiator in conjunction with the cuprous complex Cu(I)Br/bipyridine, yields a well-defined macromonomer of polystyrene with an epoxy end group. GPC, IR, and ¹H NMR analyses revealed that a low-polydispersity polystyrene with the desired functionality at the end of the chain was obtained. The photoinduced cationic polymerization of this macromonomer yielded graft and block copolymers.     

Pervaporation performance of polystyrene membrane surface with perfluoroalkyl groups

Research on the effect of various chemical groups on the pervaporation performance of membranes was very important for understanding the separation phenomenon. In this article, a polystyrene membrane with ? CF₃ groups on its surface was prepared by casting normal polystyrene (PS‐H) solution with small‐molecular‐weight α,ω‐fluoroalkyl‐terminated polystyrene (S‐PS‐(CF₃)₂) on a glass plate. The amount of ? CF₃ groups on the surface was adjusted by changing S‐PS‐(CF₃)₂ content, which was documented by X‐ray photoelectron spectroscopy analysis, surface energy, and contact angle measurements. The effect of S‐PS‐(CF₃)₂ content on separation performance of S‐PS‐(CF₃)₂/PS‐H blend membranes for ethanol/water mixture was investigated. The results showed that water concentration in the permeate decreased with increasing S‐PS‐(CF₃)₂ content; however, the permeation rate did not change until the S‐PS‐(CF₃)₂ content was increased to 1 wt %. The reason for this was attributed to the fact that a small amount of S‐PS‐(CF₃)₂ enables a simple surface modification of the membrane keeping its inner structure relatively unchanged. This was confirmed by swelling degree measurements and other experiments. Comparison with our previous work showed that the ? CF₃ groups on the surface lowers the water permselectivity of the polystyrene membranes, whereas the ? COOH groups enhance the water permselectivity. However, neither hydrophobic ? CF₃ nor hydrophilic groups on the membrane surface appeared to have any influence on flux. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007