Synthesis,characterization and computational investigation of poly(styrene-co-1-methylpyrenyl methacrylate): its efficiency as a macrophotoinitiator

Abstract

In this study, it has been demonstrated that poly(styrene-co-1-methylpyrenyl methacrylate) macro-photoinitiator (PSMM) containing side chain pyrene moieties were successfully prepared using “radical polymerization method.” Firstly, 1-pyrene methanol and methacryloyl chloride were reacted in dichloromethane for 24?h at 0?°C in order to give 1-methoxy pyrene methacrylate macromonomer. Then styrene was polymerized with this macromonomer to obtained macro-photoinitiator. The synthesized copolymer is also both computationally and experimentally demonstrated that the macro-photoinitiator obtained has similar absorption characteristics with the parent pyrene molecule. According to obtained results, the synthesized copolymer was more effective in the presence of triethyl amine as a macro-photoinitiator.     

The structuring and properties of hydrogels prepared with a biologically active macromonomer

The copolymerization of a macromonomeric inhibitor of proteolytic enzymes with acrylamide and N,N′-methylenebis(acrylamide) in an aqueous solution in the presence of a redox catalyst has been studied. It has been shown that the addition of mercaptoacetic acid as a chain-transfer agent to the polymerization system results in a change in the structure of the forming hydrogel, i.e., a decrease in the number of large pores. Simultaneously, a substantial increase in the degree of the macromonomer incorporation into the hydrogel is attained and favorable conditions for the development of the biological activity of the macromonomer are created.     

Preparation of a uniform poly(methyl methacrylate) macromonomer and its polymerization

Syndiotactic poly(methyl methacrylate) (st-PMMA) macromonomer having methacryloyl end group was prepared from st-PMMA living anion and separated into uniform macromonomers by means of supercritical fluid chromatography. A uniform macromonomer with the degree of polymerization of 32 was polymerized radically in benzene at 60°C. The uniform dimer, trimer and tetramer of the uniform macromonomer were isolated from the polymerization product by means of gel-permeation chromatography (GPC). The intrinsic viscosity ([η]) in tetrahydrofuran of these uniform comblike polymers was determined by GPC/differential viscometric analysis. The plot of logarithmic [η] against logarithmic molecular weight indicated that the trimer and tetramer assume a little shrinking molecular shape as compared with the unimer and dimer.     

Preparation and Characterization of Polymeric Microspheres Having Isotactic Poly(methacrylic acid) on Their Surfaces

IntroductionUseful strategies for the synthesis of polymer-ic particles and their surface modification have re-ceived much attention. In recent years,authorshave been interested in the preparation and thecharacterization of sub- micron to micron- sizemonodisperse polymeric particles by the emulsifier-free radical dispersion copolymerization of hy-drophilic macromonomers and hydrophobicmonomers in polar solvents.Itwas found thatwa-ter- soluble polymer chains grafted on the surfacesof the partic…     

Mesomorphic phase formation of poly (macromonomer)s of polystyrene macromonomers

The liquid crystalline phase formation of poly(macromonomer)s associated with the specific multibranched architecture of high branch density was investigated. The poly(macromonomer)s were prepared by radical chain polymerizations of ω‐methacryloyloxyethyl polystyrene macromonomers. It was confirmed that the mesomorphic phase formation depended on the branching architecture, where sufficient length of the branch chains as well as the backbone chain is crucial for the formation of the mesomorphic phase. Formation of the optically anisotropic mesophase also depended on the nature of solvent. The mesophase was observed in the cast films prepared from p‐xylene, toluene, tetrahydrofuran, carbon disulfide and chloroform but not observed for cyclohexane. The effects of the branched structure and the solvent nature were explained by repulsive interaction between the polystyrene branch chains of high branch density. The repulsive interaction increases the chain stiffness of the central backbone and also prevents the interpenetration of the polystyrene branches of different molecules in solution, which allow poly(macromonomer) molecules to arrange with the orientational order. Copyright © 2000 John Wiley & Sons, Ltd.     

Anionic polymerization of styrenic macromonomers of polyisoprene,polybutadiene, and polystyrene

Anionic polymerization and high‐vacuum techniques were used to prepare a series of well‐defined polyisoprene, polybutadiene, and polystyrene polymacromonomers. The procedure involved (1) the synthesis of styrenic macromonomers in benzene by the selective reaction of the corresponding macroanion with the chlorine of 4‐(chlorodimethylsilyl)styrene (CDMSS) and (2) the in situ anionic polymerization of the macromonomer without previous isolation. The synthesis of the macromonomers [polyisoprene macromonomer: 11 samples, weight‐average molecular weight (M_w) = 1000–18,000; polybutadiene macromonomer: 5 samples, M_w = 2000–4000; and polystyrene macromonomer: 2 samples, M_w = 1300 and 3600] was monitored by size exclusion chromatography with refractive index/ultraviolet detectors. Selectivity studies with CDMSS indicated that polybutadienyllithum had the highest selectivity, and polystryryllithium the lowest. From kinetic studies it was concluded that the polymerization half‐life times were longer but comparable to those of styrene, and they appeared to only slightly depend on the molecular weight of the macromonomer chain (at least for low degrees of polymerization of the polymacromonomer and for M_w < 7000 for the macromonomer side chain). Dependence on the polymerization degree of the polymacromonomer product was also observed. All the prepared polymacromonomers were characterized by size exclusion chromatography with refractive index, ultraviolet and two‐angle laser light scattering detectors, and NMR spectroscopy. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1038–1048, 2005     

Synthesis of a novel syndiotactic poly(macromonomer) consisting of styrene‐terminated polyisoprene macromonomers using half‐titanocene catalysts

Homopolymerization of a styrene‐terminated polyisoprene macromonomer (SIPM) by half‐titanocene catalysts in combination with methylaluminoxane (MAO) was investigated. Polymerization of the SIPM with CpTiCl₃‐MAO as the catalyst was found to proceed readily to give a high molecular weight polymer. ¹H and ¹³C NMR spectra of the poly(SIPM) after ozonolysis of the isoprene side chain revealed that poly(SIPM) is a highly syndiotactic polymer. Syndiotactic poly(SIPM) is soluble in usual solvents in spite of having highly syndiotactic sequences on its main chain and a considerable degree of polymerization.     

分散共聚法制备特殊形态高分子微球的研究

以聚乙二醇 (PEG)大分子单体为反应性稳定剂 ,在丙烯腈的分散共聚反应中添加少量苯乙烯以形成疏水性核 ,制备得到了亚微米级高分子微球 .透射电子显微镜研究表明 ,该高分子微球具有特异的形态结构 .同时研究了分散共聚体系中各种反应因素对微球形态和直径的影响 ,结果表明 ,苯乙烯单体的添加量、PEG大分子单体的浓度及分子量、混合溶剂的组成对微球直径和形态均有明显的影响 .X 射线光电子能谱 (XPS)研究结果表明 ,微球表面聚集有亲水性PEG链 ,核为疏水的聚 (丙烯腈 苯乙烯 ) ,即形成的特异形态的PEG接枝高分子微球亦为复合型结构     

Thermo- and pH-sensitive comb-type grafted poly(N,N-diethylacrylamide-co-acrylic acid) hydrogels with rapid response behaviors

Poly(N,N-diethylacrylamide) with a terminal hydroxyl end group (PDEA-OH) was synthesized by radical telomerization of N,N-diethylacrylamide (DEA) monomer using 2-hydroxyethanethiol as a chain transfer agent. Macromonomer of thermo-sensitive PDEA was synthesized by condensation reaction of PDEA-OH with acryloyl chloride. The macromonomer was characterized by FTIR and ¹H NMR, and the molecular weight was determined by GPC. Thermo- and pH-sensitive comb-type grafted poly(N,N-diethylacrylamide-co-acrylic acid) (PDEA-co-AA) hydrogels (GHs) were successfully prepared by grafting PDEA chains with freely mobile ends onto the backbone of a cross-linked (PDEA-co-AA) network. The results showed that the deswelling behavior of the hydrogels was dependent on the test temperature. At 45 °C (beneath the VPTT of the hydrogels), both the normal-type hydrogels (NHs) and comb-type grafted P(DEA-co-AA) hydrogels had lower deswelling rates. While at 60 °C (far beyond the VPTT of the hydrogels), the deswelling rates of the GHs were faster than that of the NHs. Furthermore, pulsatile stimuli-responsive studies indicated that the GHs had excellent thermo-reversibility and were superior to the NHs in the magnitude of their swelling ratios to temperature changes. However, the reversibility to pH changes was poor for both the NHs and the GHs.     

Production of nanoparticles of methyl methacrylate and butyl methacrylate copolymers by microemulsion polymerization in the presence of maleic acid terminated poly(N-acetylethylenimine) macromonomers as cosurfactant

In this study, MMA/BMA copolymer nanoparticles were synthesized in oil-in-water microemulsions that were stabilized by sodium dodecyl sulphate (SDS) and initiated by potassium persulphate KPS. Maleic acid terminated poly(N-acetylethylenimine) (PNAEI) with two different chain lengths was also included in the recipe, as a cosurfactant and a comonomer. FTIR and ¹H-NMR proved incorporation of the macromonomer in the structure. High polymerization yields were achieved upto 98%. The viscosity average molecular weights of the copolymers were in the range of 2.77-5.50 × 10⁵. The glass transition temperatures of these copolymers were between 50.0 and 63.9 °C. The average diameter of nanoparticles were in range of 40-96 nm. It was possible to produce nanoparticles smaller than 100 nm and with narrower size distributions by using much lower concentrations of SDS by including the macromonomers in the microemulsion polymerization recipe.     

特殊形态接枝高分子颗粒的合成

表面接枝高分子微球具有分子结构的可设计性 ,分散稳定性好 ,被用于高效催化剂的载体、药物释放控制和疾病治疗等生物医学领域 ,因而引起了许多高分子材料和生物医学工作者的极大兴趣[1～ 3] .我们用链转移自由基聚合法合成了一端为苯乙烯基封端的聚乙二醇 ( PEG)和聚 ( N -异丙基丙烯酰胺 )等亲水性大分子单体 .在与疏水性单体如苯乙烯等的二元分散共聚反应中 ,利用接枝共聚物在溶液中的自组装 ,制备了粒径分布均一 ,颗粒表面形态光滑 ,同时表面具有功能性高分子链的微球 [4～ 8] .传统的合成高分子微球的研究主要是以苯乙烯或甲基丙烯酸…     

Novel Synthesis of a Macromonomer Having Organosilyl and Amino Groups

Abstract

Reaction between dimethyldivinylsilane (1) and N,N′-diethyl-N-lithio-ethylenediamine (2a) in the presence of N,N′-diethylethylenediamine (3a) in THF at 20°C gave a monoadduct, 3,3-dimethyl-6-ethyl-3-sila-6,9-diaza-1-undecene (4a). An anionic self-polyaddition reaction of 4a in the presence of lithium diisopropylamide (LDA) proceeded to form oligomers. Each of the oligomers thus obtained was found to carry a polymerizable vinylsilane moiety at the oligomer chain terminal. As a result, a new type of macromonomer having alternating repeating units of ethylenediamine and organosilyl groups was synthesized. Acid-base titration showed the macromonomer to have unique characteristics on protonation of diamine moieties. Anionic polyaddition reactions between 1 and N-lithio-piperazine (2b) in the presence of piperazine (3b) also gave a macromonomer consisting of alternating repeating units of piperazine and organosilyl groups (4b). Radical copolymerizations of styrene with 5b gave comblike graft copolymers.     

Single‐pulse pulsed laser polymerization–electron paramagnetic resonance investigations into the termination kinetics of n‐butyl acrylate macromonomers

The termination of model mid‐chain radicals (MCRs), which mimic radicals that occur in acrylate polymerization over a broad range of reaction conditions, has been studied by single‐pulse pulsed laser polymerization (SP‐PLP) in conjunction with electron paramagnetic resonance spectroscopy. The model radicals were generated by initiator‐fragment addition to acrylic macromonomers that were preformed prior to the kinetic experiments, thus enabling separation of termination from the propagation reaction, for these model radicals propagate sparingly, if at all, on the timescale of SP‐PLP experiments. Termination rate coefficients of the MCRs were determined in the temperature range of 0–60°C in acetonitrile and butyl propionate solution as well as in bulk macromonomer over the range of 0–100 °C. Termination rate coefficients slightly below those of the corresponding secondary radicals were deduced, demonstrating the relatively high termination activity of this species, even when undergoing MCR–MCR termination. For chain length of 10, a reduction by a factor of 6 is observed. Unusually high activation energies were found for the termination rate coefficient in these systems, with 35 kJ mol^?1 being determined for bulk macromonomer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Syndiospecific copolymerization of styrene with styrene terminated isoprene macromonomer by CpTiCl3-methylaluminoxane catalyst

Copolymerization of styrene with styrene terminated polyisoprene macromonomer (SIPM) by CpTiCl₃-methylaluminoxane (MAO) catalyst has been investigated (Cp: cyclopentadienyl). SIPM was prepared by reaction of living polyisoprene initiated with sec-butyllithium (s-BuLi) and p-chloromethylstyrene. The synthesized macromonomer has a high terminal degree of functionalization and a narrow molecular weight distribution. Graft copolymers of polystyrene-graft-polyisoprene have been synthesized with the CpTiCl₃-MAO catalyst. The synthesized graft copolymer was confirmed to have a highly syndiotactic sequence on the main chain.     

Toward uniform polymer architecture through stereospecific living polymerization and chromatographic separation technique

Isotactic (it-) and syndiotactic (st-) poly(methyl methacrylate)s (PMMAs) were fractionated into uniform PMMAs (without molecular weight distribution) by supercritical fluid chromatography (SFC). The SFC technique was applied to the isolation of uniform it- and st-PMMAs with a hydroxy group (it- and st-PMMA-OH) at the chain end. Equimolar amounts of uniform it- and st-PMMA-OHs were coupled with sebacoyl dichloride to form uniform stereoblock PMMA. The reaction of uniform st-PMMA-OH with methacryloyl chloride gave uniform PMMA macromonomer with methacryloyl group at the chain end. The resulting uniform macromonomer was polymerized radically and the products were fractionated into uniform comblike polymers (1mer to 4mer) by means of gel-permeation chromatography (GPC). The uniform st-PMMA-OH was reacted with 1, 3, 5-benzenetricarbonyl trichloride to form uniform st-tri-armed star polymer. Some of the properties of these uniform stereoregular polymer architectures were studied.     

Precise synthesis of poly(macromonomer)s containing sugars by repetitive ROMP and their attachments to poly(ethylene glycol): synthesis, TEM analysis and their properties as amphiphilic block fragments

Various poly(macromonomer)s (PMMs) have been prepared by a repeating ring opening metathesis polymerization (ROMP) technique using the well-defined molybdenum initiators of the type, [Mo(CHCMe(2)Ph)(NAr)(OR)(2)] with OR=OCMe(3), OCMeC(CF(3))(2); Ar=2,6-iPr(2)C(6)H(3), 2,6-Me(2)C(6)H(3). The synthetic strategy is based on the polymerization of norbornene and its derivatives affording di- and triblock side chains bearing sugars (mannose, galactose, glucose etc.), linked via O- (ester), and glycosidase resistant C- (isoxazoline) glycosides. The efficient placement of norbornene units on the side chain termini and their conversion into PMMs, facilitated by the Mo alkylidenes, proceeded in a living manner with the quantitative initiation. The methodology was applied to prepare poly(macromonomer)-graft-PEG [PEG: poly(ethylene glycol)], by the attachment of a pseudo phenol terminus on the PMM main chain to PEG-Ms(2) [MsO(CH(2)CH(2)O)(n)Ms, Ms=MeSO(2)] using a "grafting to" approach. Removal of the acetal protecting groups from the sugar coating of a variety of supramolecular structures including PMMs, linear amphiphilic block copolymers (ABC) and a PMM-graft-PEGby using trifluroacetic acid/water (9:1), and suspension in water, prompted the spontaneous formation of spherical architectures by self-assembly of the amphiphilic PMMs as observed by transmission electron microscopy (TEM). The ability to uptake the hydrophobic dye (Nile Red) into the micellar cores of a variety of amphiphilic polymeric fragments is a significant step towards the production of sugar-coated nanospheres for cell-targeting biomimetic applications.     

Copolymer of poly(4-vinylpyridine)-g-poly(ethylene oxide) respond sharply to temperature, pH and ionic strength

The stimuli-responsive copolymers with poly(ethylene oxide) (PEO) as side chain were prepared by free-radical copolymerization of methacrylamide end-capped PEO macromonomer and 4-vinylpyridine (4VP). Phase transition behavior of these copolymers of poly(4-vinylpyridine)-g-poly(ethylene oxide) (P4VP-g-PEO) was investigated as a function of polymer concentration, temperature, pH and ionic strength by monitoring the turbidity of the polymer solutions. The copolymers displayed sharp response to temperature and pH. The LCST of P4VP-g-PEO copolymer increased with the increase of PEO content and decreased with increasing pH due to the deprotonation of the pyridine ring, indicating well-tunable LCST. In addition, the LCST of P4VP-g-PEO9 presented a unique phase transition behavior with varying salt concentration, showing a minimum with 1 M NaCl solution at pH 6.0.     

Emulsion and dispersion polymerization of styrene in the presence of PEO macromonomers with p-vinylphenylalkyl end groups

Poly(ethylene oxide) (PEO) macromonomers with α-p-vinylphenylalkyl (propyl, pentyl, and hexyl) and ω-hydroxy end groups were applied to emulsion and dispersion polymerization of styrene as reactive emulsifiers and dispersants in water and in methanol-water mixture (9:1 v/v), respectively. Nearly monodisperse microspheres of submicron to micron size were obtained. Particle size in the emulsion system was one or half order of magnitude smaller than that in the dispersion system, while in both systems the size decreased approximately according to minus one half power of the macromonomer concentration in weight. The particle size was substantially independent on the PEO chain length and also on the spacer alkyl chain length of the α-polymerizing end group. The total weight of the PEO chains incorporated by copolymerization into the particle surfaces (shells), relative to that of styrene polymerized into the particle cores, appears to be a key factor for controlling the particle size. To cite this article: K. Landfester et al., C. R. Chimie 6 (2003).     

A novel synthesis of semitelechelic functional poly(methacrylate)s through an alcoholate initiated polymerization. Synthesis of poly[2-(N,N-diethylaminoethyl) methacrylate] macromonomer

Potassium alcoholate was found to initiate the anionic polymerization of 2-(N,N-diethylaminoethyl) methacrylate (AMA) to form poly[2-(N,N-diethylaminoethyl) methacrylate] (PAMA). The molecular weight of the polymers was controlled by the monomer-initiator ratio with a narrow molecular weight distribution. Increased reactivity of the initiator by chelation of the monomer to the cation may be important for the polymerization. Using potassium (4-vinylbenzyl) alcoholate as an initiator, PAMA having a vinylbenzyl group was prepared which is a macromonomer having pH sensitive amino groups in each monomeric unit. By radical copolymerization with styrene, the PAMA macromonomer was incorporated as a graft chain.