甲基丙烯酸正丁酯共聚纤维的结构与性能

以甲基丙烯酸β-羟乙酯(HEMA)为第二单体,与甲基丙烯酸正丁酯(BMA)悬浮聚合制得BMA/HEMA二元共聚物,采用冻胶纺丝法制备BMA/HEMA共聚纤维,研究了加入HEMA的对纤维结构与性能的影响。结果表明:随着HEMA含量的增加,BMA/HEMA纤维分子间氢键作用和物理交联作用增强,纤维的玻璃化转变温度升高,但纤维表面变得粗糙,具有疏松多孔结构,其吸附性能提高。当HEMA质量分数为15%时,BMA/HEMA纤维对有机液体三氯乙烯的吸附量达18.5g/g。     

New interpenetrating polymer networks based on uralkyd–poly(butyl methacrylate)

A study on two‐component semi‐ and full‐interpenetrating polymer networks (IPNs) of soyabean‐oil based uralkyd resin (UA) and poly(butyl methacrylate) (PBMA) synthesized by a sequential technique, has been conducted. The IPNs obtained are characterized with respect to their mechanical properties, such as tensile strength, percentage elongation and hardness (Shore A). Phase morphology has been studied by scanning electron microscopy. Glass transition studies have been carried out using differential scanning calorimetry. The thermal characterization of the IPNs was undertaken with the aid of thermogravimetric analysis. The apparent densities of these samples have been determined and are compared. The effect of the compositional variation on the above‐mentioned properties was examined. The tensile strength exhibits a sudden rise (approximately three‐fold) for the semi‐ and full‐IPNs with composition UA: PBMA 40% : 60% compared with the UA:PBMA composition of 20% : 40%. © 2001 Society of Chemical Industry     

Nonaqueous emulsion copolymerization of ethyl methacrylate/lauryl methacrylate in propylene glycol. I. Evaluation of stabilizing efficiency for PEO‐PS‐PEO triblock copolymers

Sixteen poly(ethylene oxide)–polystyrene–poly(ethylene oxide) (PEO‐PS‐PEO) triblock copolymers were synthesized by anionic polymerization. They were characterized by gel permeation chromatography and proton NMR. The molecular weight of these 16 PEO‐PS‐PEO triblock copolymers ranged from 5100 to 13,300. The polystyrene (PS) block length was between 13 and 41. The PEO block length was between 41 and 106. The polydispersity index for these PEO‐PS‐PEO triblock copolymers were 1.05 ± 0.02. When using these stabilizers in the emulsion copolymerization of ethyl methacrylate and lauryl methacylate in propylene glycol, only a narrow window of stability was observed. Stable latexes were formed only when the molecular weights of the PEO blocks were within the range of 5300–7700 and the molecular weights of the PS blocks were 2000–4000. The stabilizer ability for these triblock copolymers was correlated with their molecular weight and conformation in propylene glycol. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1951–1962, 2001     

Compatibility studies with blends based on poly(n‐butyl methacrylate) and polyacrylonitrile

In this study, poly(n‐butyl methacrylate) (PBMA) was prepared by a suspension polymerization process, and blending with polyacrylonitrile (PAN) in N,N‐dimethyl acetamide to prepare PAN/PBMA blends in various proportions. Hansen's three dimensional solubility parameters of PAN and PBMA were calculated approximately through the contributions of the structural groups. The compatibility in these blend systems was studied with theoretical calculations as well as experimental measurements. Viscometric methods, Fourier transform infrared spectroscopy, dynamic mechanical analysis, scanning electron microscopy, and thermogravimetric analysis were used for this investigation. All the results showed that a partial compatibility existed in PAN/PBMA blend system, which may be due to the intermolecular interactions between the two polymers. And, the adsorption experiment results showed that the addition of PBMA contributed to the enhancing adsorptive properties of blend fibers, which lays the foundation for further studying PAN/PBMA blend fibers with adsorptive function. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Kinetic study of emulsion copolymerization of ethyl methacrylate/lauryl methacrylate in propylene glycol,stabilized with poly(ethylene oxide)–block–polystyrene–block–poly(ethylene oxide) triblock copolymer

The kinetics of emulsion copolymerization of ethyl methacrylate (EMA)/lauryl methacrylate (LMA) in propylene glycol is very similar to the emulsion copolymerizations of water‐soluble monomers in water because of the high solubility of EMA/LMA in propylene glycol. The initial rate of polymerization depends only on initiator concentration and is not affected by either monomer concentration or stabilizer concentration. The overall rate of polymerization is only slightly dependent on monomer concentration and stabilizer concentration and is independent of initiator concentration. The final particle number density increases with increasing amount of stabilizer and decreases with increasing monomer concentration. The total surface area increases with stabilizer concentration and is not governed by either initiator concentration or monomer concentration. Homogeneous nucleation is the dominant mechanism of particle nucleation, as shown by the kinetic data on seeded polymerization and monomer partition behavior. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1691–1704, 2001     

Radical polymerization of n‐butyl methacrylate initiated by stibonium ylide

1,2,3,4‐Tetraphenylcyclopentadiene triphenyl stibonium ylide initiated radical polymerization of n‐butyl methacrylate (n‐BMA) in dioxane at (60 ± 0.2)°C for 90 min under nitrogen atmosphere has been carried out. The system follows nonideal kinetics, i.e., R_p α [ylide]^0.2 [n‐BMA]^1.8. The value of k/k_t and overall energy of activation have been computed as 0.133 × 10^?2 L mol^?1 s^?1, 33 kJ/mol, respectively. The FTIR spectrum shows a band at 1745 cm^?1 due to acrylate group of n‐BMA. The ¹H NMR spectrum shows a peak of two magnetically equivalent protons of methylene group at 2.1 δ ppm. The DSC curve shows glass transition temperature (T_g) as 41°C. The presence of six hyperfine lines in ESR spectrum indicates that the system follows free radical polymerization and the initiation is brought about by phenyl radical. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2457–2463, 2007     

均相制备纤维素/丙烯酰胺/甲基丙烯酸丁酯接枝共聚物的研究

以氢氧化钠/硫脲/尿素新型溶液溶解纤维素,在均相条件下以丙烯酰胺(AM)、甲基丙烯酸丁酯(BMA)为接枝单体,过硫酸铵为引发剂,N,N′-亚甲基双丙烯酰胺(MBA)为交联剂,通过自由基聚合法制备出了纤维素/AM/BMA接枝共聚物。考察了聚合温度、时间以及(NH4)2S2O8、AM、BMA、MBA的用量对接枝效果的影响。利用红外光谱(FT-IR)、X射线衍射(XRD)和扫描电镜(SEM)对接枝产物进行了结构表征。实验结果表明,纤维素/AM/BMA接枝共聚物的最佳合成条件为:m(纤维素)∶m(AM)∶m(BMA)∶m[(NH4)2S2O8]∶m(MBA)=1∶4∶2∶0.05∶0.006,反应温度为65℃,反应时间为2h,在此条件下接枝率可达87%,接枝效率为36%。制备的纤维素/AM/BMA接枝共聚物的吸水倍率为583g/g。     

Enrichment of poly(butyl methacrylate) and its graft copolymer of polybutadiene on the surface of polypropylene blend

The enrichment and diffusion of poly (butyl methacrylate) (PBMA) and its graft copolymer of polybutadiene on the surface of polypropylene (PP) blends were investigated using attenuated total reflection infrared spectroscopy (ATR‐FTIR), contact angle measurements (CDA), and scanning electron microscopy (SEM). It has been found that the selective aggregation of the PBMA and its copolymers on the surface of blends is mainly affected by the content, molecular weight, and the segregated domains. Lower content and higher surface energy die are in favor of the enrichment of additives on the surface of PP. PBMA with higher molecular weight has lower diffusivity and bigger phase domains, which results in its lower enrichment on the surface of PP blend film. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Functionally gradient silicone sheet made by treatment of swelling and polymerization with n‐butyl methacrylate

A silicone sheet was dipped into n‐butyl methacrylate monomer including benzoyl peroxide and was swollen for 0.5 h at 23°C. Then, the sheet was put into a glass tube equipped with a three‐way stopcock and was deoxygenated by freezing under dry nitrogen. Polymerization was carried out by heating at 80°C for 2 h under dry nitrogen. The resultant sheet was a component gradient silicone sheet with poly‐n‐butylmethacrylate. The content of poly‐n‐butylmethacrylate increased gradually from either surface to the middle of the sheet. This phenomenon was assumed to occur because of the volatilization of n‐butyl methacrylate monomer during the polymerization. The properties of the sheet include increased tear strength and decreased gas permeability. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3152–3155, 2002; DOI 10.1002/app.10177     

Influence of shear stress treatment on stress‐strain properties of methyl methacrylate‐crosslinked butyl acrylate core‐shell polymers

The incorporation of multilayer toughness modifiers to glassy polymers proceeds frequently by kneading the polymers in a molten state. This process influences the primary structure of the modifier and the properties of the blend in dependence on a shear stress intensity. In this article, we compare the properties of polymer materials prepared from a multilayer poly(methyl methacrylate) core, butyl acrylate copolymer interlayer, and methyl methacrylate copolymer shell particles {P[MMA‐(BAC‐co)‐(MMA‐co)]} by press‐molding from powder and from polymer obtained by stirring a melt of this powder in the chamber of a Brabender mixer (200°C, 60 rpm, 10 min). The powder is obtained from a latex by coagulation after polymer synthesis in emulsion. Tensile testing shows different responses of the particle polymers when crosslinked in the middle layer by diallylphthalate (DAP) or by triallylcyanurate (TAC). Although many of the properties of the samples with DAP are improved by kneading, the presence of TAC in polymer particles led mostly to less desirable properties. The maximum percent strain in the polymer with 4.2 wt % of DAP upon shearing increases from 27% to 50%. In the samples with 4.5% TAC the maximum percent strain falls from 39% to 7%. Comparison of Young's modulus E for identical samples shows an analogous effect: a shift from 429 MPa to 638 MPa and from 624 MPa to 548 MPa. The design of the polymer particles used in this work leads to the conclusion that stress during kneading induces a partial desintegration of the crosslinked cage around the particle core. Thus, the varied behaviors of polymers used in this study are connected with the BAC‐co network structure and its transformations during the shear stress treatment of the initial polymer material. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 493–501, 1999     

Synthesis of novel high oil‐absorption resins of poly(methyl methacrylate–butyl methacrylate) by surface‐initiated atom transfer radical polymerization using activators regenerated by electron transfer for efficient removal of oil

Oil‐absorption resins are considered one of the effective materials to separate organic chemical compounds from oily water. In this work, well‐defined high oil‐absorption resins of poly(methyl methacrylate–butyl methacrylate) grafted onto silica gel were prepared by surface‐initiated atom transfer radical polymerization using activators regenerated by electron transfer mediated by FeCl₃/iminodiacetic acid. The grafted polymers were grown in a controlled manner. By considering the effect of different polymerization conditions, we prepared novel high oil‐absorption resins. The chemical structures of the resins were determined by Fourier transform IR spectroscopy. SEM and TGA were also used to characterize the resins. It was found that the resins had good heat‐resistant quality, higher oil absorbency and better oil retention and regeneration properties. The resins can absorb 31.2 g g^?1 for tricholoromethane and 23.3 g g^?1 for toluene. Copyright © 2012 Society of Chemical Industry     

Studies of crosslinked styrene–alkyl acrylate copolymers for oil absorbency application. I. Synthesis and characterization

The prepolymers for a novel oil absorbent were synthesized by copolymerizing styrene with 2‐ethylhexyl acrylate (EHA), lauryl acrylate (LA), lauryl methacrylate (LMA), and stearyl acrylate (SA). Suspension polymerization was carried out using benzoyl peroxide (BPO) as an initiator with a varying monomer feed ratio, and the copolymers were characterized by FTIR, ¹H‐NMR, DSC, and a solubility test. The copolymers were random copolymers with a single phase, and their compositions were similar to those in the monomer feed. The T_g of the copolymer could be controlled by varying the styrene/acrylate ratio. Acrylates introduced the crosslinking to linear polymers as a side reaction. Crosslinked copolymers were synthesized by adding divinylbenzene (DVB) as a crosslinking agent. At a low degree of crosslinking (0.5 wt % DVB), the T_g of the crosslinked copolymers was lower than or similar to that of the uncrosslinked ones. At a high degree of crosslinking, the T_g increased with increasing crosslinking density. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 903–913, 2000     

Homopolymerization of n‐butyl methacrylate using bis(salicylaldiminate)copper(II)/ methylaluminoxane catalysts

Polymerization catalysts based on copper precursors appear particularly interesting due to the low metal cost, limited toxicity and modest sensitivity to deactivation by polar species. To date, α‐olefin and polar monomer coordination polymerization catalysed using copper catalysts has been scarcely investigated, and a good part of the literature is represented by patents. Here this research has been expanded to the study of the performances of bis(salicylaldiminate)copper(II)/methylaluminoxane (MAO) catalysts in the polymerization of n‐butyl methacrylate. The study of the catalytic activity of bis(salicylaldiminate)copper(II)/MAO systems in n‐butyl methacrylate polymerization was focused on the relationship between the catalytic behaviour and the main reaction conditions and ligand structures. The electronic and steric characteristics of the chelate ligands play an important role in the catalytic performances. The presence of electron‐withdrawing nitro groups on the chelate ligands increased the catalytic activity which reached 36 kg_polymer mol^?1 h^?1, the highest value up to now reported for copper systems in methacrylic or acrylic monomer polymerization. These performances were ascribed to copper catalysts activated by MAO: without copper precursor, working in the presence of MAO and free salicylaldimine ligand, complete inactivity was ascertained. Copyright © 2010 Society of Chemical Industry     

Nonaqueous emulsion copolymerization of ethyl methacrylate/lauryl methacrylate in propylene glycol. II. Adsorption of poly(ethylene oxide)–polystyrene–poly(ethylene oxide) triblock copolymer on latex particles

The adsorption behavior of various poly(ethylene oxide)–polystyrene–poly(ethylene oxide) (PEO‐PS‐PEO) triblock copolymer (TBC) s on acrylic latex particles in propylene glycol was studied. The composition of the PEO‐PS‐PEO triblock polymers varied from 41 to 106 in each PEO block length and from 18 to 41 in the PS block length. The location of the PEO‐PS‐PEO TBC was determined by analyzing for the physically adsorbed amount on the latex surface, the anchored mount on the surface, the entrapped amount inside the particle, and the “free” PEO‐PS‐PEO TBCs in the propylene glycol. A contour graph technique was applied to analyze the experimental data, which showed that a minimum existed for the physically adsorbed portion at a PS block length of about 30 units. When the PS block length was less than 30 units, the adsorption decreased with increasing PS block length, indicating rearrangement of mixed PEO brush and adsorbed PS block. When the PS block was greater than 30 units, the adsorption increased with increasing block length because of the poor solvency of the PS block in the propylene glycol medium, resulting in a collapse of the PS chain. Considering the binding energy between the PS block and the latex particle surface, which governs adsorption, it was hypothesized that a lower block length limit exists, below which no adsorption takes place. The solubility of the PS block in propylene glycol guides the important upper block length limit. The anchored fraction of the block copolymer increased continuously with increasing PS block length in the entire region investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1963–1975, 2001     

Synthesis and application of methyl methacrylate/butyl acrylate copolymer nanoemulsions as efficient retanning and lubricating agents for chrome‐tanned leather

Two different nano‐emulsions based on methyl methacrylate/butyl acrylate copolymers have been synthesized to be used as retanning and lubricating agents for chrome‐tanned leather. The main difference and characteristics of the two prepared copolymers were studied. The nano particle size of the two copolymers was confirmed using transmission electron microscope (TEM). The influence of the prepared copolymers on chrome‐tanned leather as retanning agents was investigated. The properties of the retanned leather, namely, physicomechanical properties as tensile strength, elongation at break and water absorption, were measured. Thermal gravimetric analysis (TGA) technique was used to examine the thermal stability of the retanned leather. Also, the texture of the grain surface and fibers were inspected using scanning electron microscope (SEM). The retanned leather showed an improvement in its physicomechanical properties, as well as enhancement of its thermal stability as compared with the chrome‐tanned leather. Furthermore, the retanned leather has uniform dyestuff, softness, and firmness of grain. All these promising results provide evidence to the applicability of the prepared copolymer emulsions as efficient retanning and lubricating agents for chrome‐tanned leather. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Morphology and spherulitic growth kinetics in poly(ethylene oxide)/poly(n‐butyl methacrylate) blends

Results of a study concerning the morphology and the spherulite growth rates of poly(ethylene oxide) (PEO) in binary blends with poly(n‐butyl methacrylate) (PnBMA) are reported. Microscopic observations show that blending causes the spherulite structure to become coarser and less birefringent and confirms that the spherulitic growth rates of PEO were reduced by the addition of PnBMA. X‐ray diffraction studies show no change in the unit cell dimensions and a decrease in the degree of crystallinity upon blending. Analysis of the spherulite radial growth rate data by using Lauritzen–Hoffman theory indicates that crystallization in the range of 300 to 330 K occurs solely within regime III. The calculated surface free energy of folding, σ_e, for pure PEO is 57 erg cm^?2 and decreases with increasing the content of PnBMA in the blend. Copyright © 2004 Society of Chemical Industry     

Effect of crosslinking concentration on mechanical and thermodynamic properties in acrylic acid–co–methyl methacrylate hydrogels

The mechanical and thermodynamic properties of poly(acrylic acid‐co‐methyl methacrylate) hydrogels with varying crosslinker N,N′‐methylenebisacrylamide (NMBA) content are reported. A higher NMBA content generally led to a stronger and harder gel with lower water content. Swelling capacity decreased as the NMBA concentration increased between 0.5% and 2%, remaining constant beyond this range. The temperature changes of the partial molar Gibbs free energy of dilution and enthalpic and entropic contributions were examined. The thermodynamic parameters showed that swelling was an unfavorable and endothermic process. The freezing and nonfreezing water in the hydrogel was determined by differential scanning calorimetry (DSC). Freezing water content decreased with increasing crosslinker (NMBA) content, whereas the ratio of nonfreezing water to total water content increased with NMBA content because of the promoting of hydrophobic interactions in the hydrogels. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4016–4022, 2006     

A kinetic study on polymerization of methyl methacrylate with di‐t‐butyl perfumarate

Di‐t‐butyl perfumarate (DBPF) was found to induce the radical polymerizations of various vinyl monomers at 60°C in benzene, although the initiation activity was considerably lower than those of dimethyl 2,2′‐azobisisobutyrate and benzoyl peroxide. The polymerizations with DBPF showed a tendency of dead‐end polymerization. The polymerization of methyl methacrylate (MMA) with DBPF was kinetically studied in chlorobenzene. The initial polymerization rate (R_p) was given by R_p = k [DBPF]^0.5 [MMA]^1.1. The overall activation energy of the polymerization was 47 kJ/mol, a very low value. Use of this value and activation energies of propagation and termination for MMA gave an unexpectedly low activation energy (65 kJ/mol) to the decomposition of DBPF, a t‐butyl perester, in the polymerization system. An ESR study on the polymerization of di‐2‐ethylhexyl itaconate with DBPF revealed that the observed dead‐end tendency comes from the consumption of DBPF. These results suggest that the initiator efficiency of DBPF is considerably low in the present polymerization systems. Some solvent effect was observed on the polymerization of MMA with DBPF. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 218–224, 2000     

Preparation and properties of core [poly(styrene‐n‐butyl acrylate)]–shell [poly(styrene–methyl methacrylate–vinyl triethoxide silane)] structured latex particles with self‐crosslinking characteristics

Structured latex particles with a slightly crosslinked poly(styrene‐n‐butyl acrylate) (PSB) core and a poly(styrene–methacrylate–vinyl triethoxide silane) (PSMV) shell were prepared by seed emulsion polymerization, and the latex particle structures were investigated with Fourier transform infrared, thermogravimetric analysis, differential scanning calorimetry, transmission electron microscopy, and dynamic light scattering. The films that were formed from the structured core (PSB)–shell (PSMV) particles under ambient conditions had good water repellency and good tensile strength in comparison with films from structured core (PSB)–shell [poly(styrene–methyl methyacrylate)] latex particles; this was attributed to the self‐crosslinking of CH₂?CH? Si(OCH₂CH₃)₃ in the outer shell structure. The relationship between the particle structure and the film properties was also investigated in this work. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1824–1830, 2006