Microstructure of the chain of alkyl (meth)acrylate copolymers with vinyl butyl ether synthesized by the compensation method

Russian Chemical Bulletin - Copolymers of butyl acrylate and methyl methacrylate with vinyl butyl ether in excess at reflux of the latter were synthesized under comparable conditions gradually...     

Specific features of nickel-catalyzed synthesis of poly(butyl (meth)acrylates)

The activity of the catalytic system NiBr₂(PPh₃)₂/Zn/PhI in polymerization of butyl acrylate and butyl methacrylate and in copolymerization of butyl methacrylate with styrene was examined.     

On the synthesis of pure (meth) acrylate esters and their corresponding homopolymers

We have observed that homopolymers of certain (meth)acrylate esters, prepared by the Schotten–Baumann method of (meth)acryloyl chloride and desired alcohol, in the presence of triethylamine or pyridine, formed gels. The mechanism of gelation was investigated and found to be due to a diene impurity, (meth)acrylic anhydride, which cannot be easily separated from many (meth)acrylate esters. For preparation of pure (meth)acrylate esters, the S_N2 displacement reaction of (meth)acrylate anion with the desired chloro compound is recommended. The yields of the two reactions are comparable, and even t-butoxycarbonylmethyl methacrylate is produced in 73% yield by the recommended method.     

Preparation of styrene-(meth)acrylate copolymers in the presence of 1-nitroso-2-naphtholatocobalt(III)

Preparation of styrene-methyl methacrylate, styrene-butyl methacrylate, and styrene-butyl methacrylate copolymers by pseudolive radical polymerization was studied.     

核-壳型聚丙烯酸酯复合乳液

简述了核-壳型聚丙烯酸酯复合乳液的合成方法、形态及其影响因素与判断方法、结构与性能等方面的研究进展;认为核-壳型复合乳液膜机械性能优良的原因是:核、壳两相间存在的过渡区适当地抑制了二者的相分离。     

Tailored synthesis of structurally defined polymers by organotellurium-mediated living radical polymerization (TERP): synthesis of poly(meth)acrylate derivatives and their di- and triblock copolymers

The organotellurium-mediated living radical polymerization (TERP) method allows the synthesis of various polyacrylate and polymethacrylate derivatives with precise control of molecular weight and with defined end groups. The method can be applied to the synthesis of AB-diblock and ABA- and ABC-triblock copolymers composed of different families of monomers.     

Synthesis and utility of ethylene (meth)acrylate copolymers prepared by a tandem ring-opening polymerization hydrogenation strategy

One new and one established functional cyclooctene were prepared and (co)polymerized using ring-opening metathesis polymerization. The resulting polymers were hydrogenated to yield the corresponding functional polyolefins that were structurally equivalent to copolymers of ethylene and either methyl methacrylate, t-butyl acrylate, or acrylic acid after deprotection. The copolymers that incorporate methyl methacrylate into the backbone were used as compatibilizers for poly(methyl methacrylate)/polyethylene blends. The copolymers that incorporate t-butyl acrylate into the backbone yielded elastomers that could be thermally crosslinked. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3117–3126     

Effect of branching and molecular weight on the viscoelastic properties of poly(butyl acrylate)

A series of poly(butyl acrylate) samples were prepared by emulsion polymerization with a range of molecular weights and degrees of chain branching. Characterization was performed with NMR (giving the fraction of branching, ranging from approximately 0 to 7%), gel permeation chromatography, viscometry, and determination of the gel fraction. The dynamic mechanical response, that is, the frequency dependence of the storage and loss moduli G′(ω) and G″(ω) was measured from 0.02 to 200 Hz. The occurrence of a significant insoluble fraction in the sample meant that full characterization of the molecular weight distribution was not possible, and so an unambiguous separation of the dependencies of the mechanical response on the degree of long‐chain branching (LCB) and short‐chain branching (SCB) and the molecular weight could not be made; however, trends dependent on the molecular weight alone were insufficient to model the results. At high frequencies, all trends in G′(ω) and G″(ω) could be ascribed to molecular weight dependencies; at low frequencies, the effects of both the molecular weight and total degree of branching could be inferred, with more highly branched samples showing lower storage and loss moduli. Although the relative amounts of SCB and LCB could not be determined, no dynamic features attributable to LCB were observed. The low‐frequency trends could be semiquantitatively fitted with reptation and retraction theory if it was assumed that an increased degree of SCB led to an increased tube size. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3335–3349, 2002     

Straightforward synthesis of poly(lauryl acrylate)-b-poly(stearyl acrylate) diblock copolymers by ATRP

Lauryl (LA) and stearyl (SA) acrylates were successfully polymerized by atom transfer radical polymerization (ATRP), leading to well defined homopolymers and diblock copolymers (PDI < 1.2). Interestingly, the polymerization was very well controlled using N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA), a ligand which had initially been reported to be unadvisable for the polymerization of such monomers. Both kinetic studies and chain extension reactions supported our conclusions. A PLA₆₅-b-PSA₄₇ diblock copolymer was characterized by differential scanning calorimetry and dynamic thermo-mechanical analysis, revealing that both blocks exhibit side-chain crystallinity and phase segregate in the crystalline state. The diblock behaves as a brittle rigid polymer when both blocks are crystalline, as a ductile material after the melting of the PLA phase and becomes a viscous liquid when both blocks are molten. This work could be extended to the preparation of PSA-b-PLA-b-PSA bio-issued thermoplastic elastomers.     

Transparent inorganic/organic copolymers by the sol-gel process: Thermal behavior of copolymers of tetraethyl orthosilicate (TEOS), vinyl triethoxysilane (VTES) and (meth)acrylate monomers

Three types of inorganic/organic copolymers have been prepared in a one-step sol-gel process, and their thermal stabilities have been studied. The one-step sol gel process was carried out in mixtures of three monomeric components: HEMA (hydroxyethyl methacrylate)-VTES (vinyl triethoxysilane)-TEOS (tetraethyl orthsilicate), HDDA (hexanediol diacrylate)-VTES-TEOS and GPTA (glycerol propoxy triacrylate)-VTES-TEOS. Copolymers with HEMA, which is able to form a linear organic polymer, were the least thermally stable materials. They lost the highest proportion of weight during heat treatment to 600°C and exhibited the lowest decomposition temperatures. Copolymers with HDDA and GPTA, which are able to form crosslinked organic polymers, had higher decomposition temperatures, and their weight loss during heat treatment to 600°C was small. The skeletal densities of all copolymers increased slightly during heat treatment.     

Synthesis of pentafluorophenyl(meth)acrylate polymers: New precursor polymers for the synthesis of multifunctional materials

Pentafluorophenyl acrylate and -methacrylate were polymerized using AIBN as a thermal initiator. The obtained polymers were soluble polymeric active esters that could be used for the preparation of multifunctional polymers. The reactivity of poly(pentafluorophenylacrylate) and poly(pentafluorophenylmethacrylate) towards primary and secondary amines, as well as alcohols was investigated in a quantitative way. Both poly(active esters) reacted satisfactorily with aliphatic primary and secondary amines but only low conversion was found in the case of aromatic amines. Conversions of only 30% were reached when poly(pentafluorophenylacrylate) was treated with one equivalent of alcohol under base catalysis. In time resolved FT-IR studies the rate constants of the polymer analogous reactions were determined.     

Synthesis and characterization of functional gradient copolymers of allyl methacrylate and butyl acrylate

Functional spontaneous gradient copolymers of allyl methacrylate (A) and butyl acrylate (B) were synthesized via atom transfer radical polymerization. The copolymerization reactions were carried out in toluene solutions at 100 °C with methyl 2‐bromopropionate as the initiator and copper bromide with N,N,N′,N″,N″‐pentamethyldiethylenetriamine as the catalyst system. Different aspects of the statistical reaction copolymerizations, such as the kinetic behavior, crosslinking density, and gel fraction, were studied. The gel data were compared with Flory's gelation theory, and the sol fractions of the synthesized copolymers were characterized by size exclusion chromatography and nuclear magnetic resonance spectroscopy. The copolymer composition, demonstrating the gradient character of the copolymers, and the microstructure were analyzed. The experimental data agreed well with data calculated with the Mayo–Lewis terminal model and Bernoullian statistics, with monomer reactivity ratios of 2.58 ± 0.37 and 0.51 ± 0.05 for A and B, respectively, an isotacticity parameter for A of 0.24, and a coisotacticity parameter of 0.33. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5304–5315, 2006     

Photochemical synthesis of gold nanoparticles in elastomer films of poly(butyl acrylate) latex

Gold particles are formed by photochemical reduction of HAuCl₄ in the bulk of poly(butyl acrylate) elastomer films under the action of monochromatic light with the wavelengths of 254 and 365 nm with direct participation of the ester chromophore group of the polymer having intrinsic photosensitivity in the near-UV range (254 nm). On irradiation at the wavelength of 365 nm, the reduction of HAuCl₄ is ineffective and stops at the stage of Au(I) formation. The physicomechanical properties of elastomer films modified with gold particles (tensile strength and relative elongation) were studied.     

聚乙烯醇和丙烯酸-β-羟乙酯水凝胶的摩擦学特性

合成水凝胶是由水溶性单体聚合得到的轻度交联的高分子柔顺链网络 .高分子交联网络与水之间的相互作用决定着水凝胶的物理化学性质[1,2 ] .水凝胶常应用于生物医学材料和生物传感器等方面 .如接触眼镜的材料就常用甲基丙烯酸 -β-羟乙酯和聚乙烯醇 (PVA)为主要成分的水凝胶 ,所以对其摩擦性质的研究会丰富对生物医用材料的认识 .关于水凝胶的摩擦性质的研究 ,除 Osada等[3] 研究了聚乙烯醇及一些天然水凝胶在几牛顿到几十牛顿的负载下的摩擦行为外 ,尚少报道 .PVA水凝胶的结晶度对其性能影响甚大 ,但他们没有涉及结晶度与 PVA水凝胶的摩…     

Controlled radical polymerization of tert‐butyl acrylate at ambient temperature: Effect of initiator structure and synthesis of amphiphilic block copolymers

Controlled and very rapid ambient temperature polymerization of tert‐butyl acrylate (tBA) via atom transfer radical polymerization (ATRP) and single electron transfer living radical polymerization (SET‐LRP) conditions is reported. Two initiators, one that would generate a secondary radical and another that would generate a primary radical, upon activation, are used. A very active catalyst CuBr/Me₆TREN was found to initiate rapid polymerization whether it was the primary or the secondary initiator. The polymerization was well controlled and very rapid. The initiator that produces secondary initiating site is found to result in more rapid polymerization than the one that produces primary initiating site. To explore the possibility of rapid ambient temperature polymerization through the SET‐LRP mechanism, the polymerization was also carried out in the presence of DMSO. It was found that the polymerization was much faster compared to the bulk ATRP, without loss of control. Styrene was block copolymerized from PtBA macroinitiators and vice versa. In both the cases, block copolymers with controlled molecular weights were obtained. The tBA block of the polymer was selectively hydrolyzed to get amphiphilic block copolymers. This amphiphilic block copolymer was found to be useful in preparing stable cadmium sulfide (CdS) nanoparticulate dispersion. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Mechanical properties of gradient copolymers of styrene and n‐butyl acrylate

The mechanical properties of linear and V‐shaped compositional gradient copolymer of styrene and n‐butyl acrylate with composition of around 55 wt % styrene were investigated by comparing with their block copolymer counterparts. Compared with their block copolymer counterparts, the gradient copolymers showed lower elastic modulus, much larger elongation at break, and similar ultimate tensile strength at room temperature. This performance could be ascribed to that the local moduli continuously change from the hardest nanodomains to the softest nanodomains in the gradient copolymer, which alleviates the stress concentration during tensile test. Compared with the V‐shaped gradient (VG) copolymer, the linear gradient copolymer showed much higher elastic modulus but lower elongation at break. The mechanical properties of the gradient copolymers were more sensitive to the change in temperature from 9 °C to 75 °C. With recovery temperature increased from 10 °C to 60 °C, the strain recovery of VG copolymer would change steadily from 40% to 99%. However, the elastic recovery of linear and triblock copolymer was poor even at 60 °C. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 860–868     

Transparent inorganic/organic copolymers by the Sol-Gel process: Copolymers of tetraethyl orthosilicate (TEOS), vinyl triethoxysilane (VTES) and (meth)acrylate monomers

Vinyl triethoxysilane (VTES) and (meth)acrylate monomers were mixed to create covalently bonded inorganic/organic copolymers, with and without tetraethyl orthosilicate (TEOS). Vinyl groups underwent free radical polymerization along with copolymerization with (meth)acryl groups of the monomer. For the two-monomer system, (meth)acrylate monomer and VTES, polymerization resulted in mechanically strong copolymers with flexure strengths greater than 40 MPa. Three-component materials obtained by polymerization of (meth)acrylate monomer, VTES and TEOS were homogeneous, highly transparent, with flexure strengths similar to those for silica xerogels, about 20 Mpa.     

Synthesis of (meth)acrylate Block Copolymers by Ligated Anionic Polymerization

Synthetic potential of the ligated anionic polymerization (LAP) of acrylic and metacrylic esters initiated with methyl 2-lithioisobutyrate (MIB-Li) in the presence of an excess of alkali metal tert-alkoxides (prevailingly Li tert-butoxide) is presented. tert-Alkoxides form with ester-enolates, like MIB-Li, cross-aggregates of various composition, which tailor the environment of growing chain-ends, lower their nucleophilicity and restrict in this way the extent of side reactions, in particular self-termination of growing macroanions by back-biting reaction. Thus, stability of polymethacrylate living chains is sufficiently high for methacrylate and acrylate block copolymers to be synthesized. In the case of acrylate polymerization, reaction conditions must be optimized due to their high tendency to self-termination.