多官能度水性光敏聚氨酯丙烯酸酯的合成及性能研究

用异佛尔酮二异氰酸酯(IPDI)、丙三醇、聚四氢呋喃醚二醇(PTMG)、甲基丙烯酸羟乙酯(DMPA)、季戊四醇三丙烯酸酯(PETA)等原料合成了具有高交联度的多官能度紫外光固化聚氨酯丙烯酸酯(PUA)水乳液。采用国标GB12009.4—89,FT-IR,13C NMR,DMA,AFM等方法对PUA预聚体合成过程和聚合物乳液(涂膜)进行了测试和表征,考察了n(IPDI)∶n(HO—OH)∶n(丙三醇)、DMPA质量分数、pH值等对乳液及涂膜性能的影响。结果表明,随着丙三醇质量分数增大,PUA光固化速率、耐溶剂性、膜硬度提高、吸水率降低;随着DMPA质量分数的增加,PUA涂膜硬度、吸水率增强,乳胶粒径越来越小;随着中和度增大,乳液逐渐由云雾状趋向透明,粘度下降。当n(IPDI)∶n(HO—OH)∶n(丙三醇)=9∶6∶1,w(丙三醇)=2%左右,DMPA质量分数为4.6%,中和度为90%时,乳液储存稳定(30 d),涂膜光固化速率达到7 s,附着力为1,硬度为3 H,耐水性、耐化学品性更佳。     

Surface properties and chain structure of fluorinated acrylate copolymers prepared by emulsion polymerization

The fluorinated copolymer poly (MMA–co–FMA), composed of methyl methacrylate (MMA) and 2-perfluorooctylethyl methacrylate (FMA), was prepared by emulsion polymerization using a pre-emulsified monomer addition process. The results showed that the contact angle of water on its solvent-borne film increased dramatically and reached 118o when the FMA content in the copolymer was only 0.65 mol%, approaching that of poly(2-perfluorooctylethyl methacrylate) homopolymer. Unlike the copolymer prepared by solution polymerization, X-ray photoelectron spectroscopy (XPS), and sum frequency generation (SFG) vibrational spectroscopy analysis results indicated that the fluorinated moieties in this polymer were very easily segregated at the surface of the film. The interfacial structure and properties of this polymer in solution were investigated using SFG, surface tension, and dynamic laser light scattering (DLS). It was found that emulsion polymerization produced a chain structure of the fluorinated copolymer similar to that of FMA capped PMMA, thereby providing a possible way to produce fluorinated end-capped polymers using a popular polymerization method.     

聚合反应速率对ESBR结构与性能的影响

研究在工业丁苯装置中聚合反应速率对乳聚丁苯橡胶（ESBR）结构与性能的影响。结果表明，随聚合反应速率的增大，ESBR的重均相对分子质量增大，数均相对分子质量减小，相对分子质量分布变宽；ESBR分子链中苯乙烯链节比例略有提高，丁二烯链节中1，2-结构和顺式1，4-结构含量略有增大；ESBR生胶门尼粘度、硫化胶定伸应力和拉伸强度略有增大，拉断伸长率略有减小。     

Effect of polymerization method on structure and properties of cationic polyacrylamide

Acrylamide and 2‐(methacryloyloxy)ethyltrimethylammonium chloride (AM/MADQUAT) copolymers were synthesized by solution and inverse microemulsion polymerization using (NH₄)₂S₂O₈/NaHSO₃ as redox initiator at the same feed mole ratio, and their microstructure, such as sequence distribution and composition distribution, was calculated from monomer reactivity ratios of different polymerization methods. The results show that charge distribution is more uniform for copolymer prepared in inverse microemulsion than that in solution, and copolymer composition distribution is close to unity, and maintains approximately at the feed ratio. Furthermore, the influence of the two structures of cationic polyacrylamides on kaolinite floc size and effective floc density, reduction of Zeta potential and floc compressive yield stress had been investigated at pH 7. The results show that the kaolinite floc size and effective floc density are strongly dependent upon copolymer microstructure, with greater floc size and lower effective floc density being observed for copolymer prepared in inverse microemulsion than for that in solution. Copolymer microstructure has a marked effect on the Zeta potential, whose reduction in the magnitude was much greater in the presence of copolymer prepared in inverse microemulsion than that in solution. Greater compressive yield stress was achieved for the strong flocs produced by copolymer prepared in inverse microemulsion than for the weak flocs produced by that in solution. The difference in flocs compressive yield stress may be attributed to flocs structure. Therefore, in this article, a correlation between the cationic polyacrylamide structure and flocculation property for kaolinite suspension was established. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

氧化还原引发剂对丙烯酸酯乳液性能及聚合机制的影响

以过硫酸钾(KPS)和亚硫酸氢钠(NaHSO3)为自由基聚合体系的氧化-还原型引发剂,以十二烷基硫酸钠(SDS)和脂肪醇聚氧乙烯醚硫酸钠(AES)为阴/非离子型复合乳化剂,制备甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)和甲基丙烯酸(MAA)共聚物乳液。研究了引发剂种类及用量对该乳液性能及聚合过程等影响,探讨并提出了酸性条件下丙烯酸酯乳液体系的新型引发机制。结果表明:在其他条件保持不变的前提下,当m(KPS):m(NaHSO3)=1.00:0.45、w(KPS+NaHSO3)=0.6%时,乳液的单体转化率(98%)和黏度(5.900 Pa.s)相对最高,反应时间(2.0 h)相对较短且初始聚合温度(60℃)相对最低,此时乳液质量最稳定。     

Effect of chemical structure and crosslinking density on the thermo-mechanical properties and toughness of (meth)acrylate shape memory polymer networks

The objective of this work is to characterize and understand structure-mechanical property relationships in (meth)acrylate networks. The networks are synthesized from mono-functional (meth)acrylates with systematically varying sidegroup structure and multi-functional crosslinkers with varying mole fraction and functionality. Fundamental trends are established between the network chemical structure, crosslink density, glass transition temperature, rubbery modulus, failure strain, and toughness. The glass transition temperature of the networks ranged from −29 to 112 °C, and the rubbery modulus (E_r) ranged from 2.8 to 129.5 MPa. At low crosslink density (E_r < 10 MPa) network chemistry has a profound effect on network toughness. At high crosslink densities (E_r > 10 MPa), network chemistry has little influence on material toughness. The characteristic ratio of the mono-functional (meth)acrylates' components is unable to predict trends in network toughness as a function of chemical structure, as has been demonstrated in thermoplastics. The cohesive energy density is a better tool for relative prediction of network mechanical properties. Due to superior mechanical properties, networks with phenyl sidegroups are further investigated to understand the effect of phenyl sidegroup structure on toughness.     

Atom transfer radical polymerization of methyl acrylate from a multifunctional initiator at ambient temperature

A multifunctional initiator for ATRP has been synthesized by reacting a hyperbranched polyether, based on 3-ethyl-3-(hydroxymethyl)oxetane, with 2-bromo-isobutyrylbromide. The macroinitiator contained approximately 25 initiating sites per molecule. It was used for the atom transfer radical polymerization of methyl acrylate mediated by Cu(I)Br and tris(2-(dimethylamino)ethyl)amine (Me₆-TREN) in ethyl acetate at room temperature. This yielded a co-polymer with a dendritic-linear architecture. The large number of growing chains from each macromolecule increases the probability of inter-and intramolecular reactions. In order to control these kinds of polymerizing systems and prevent them from forming a gel, the concentration of propagating radicals must be kept low. The polymerizations under these conditions were well controlled. When a ratio of initiating sites-to-catalyst of 1:0.05 was used, the polymers from all of the reactions had a low polydispersity, ranging from 1.1 to 1.4. None of the polymerizations under these conditions gave gelation. Monomer conversions as high as 65% were reached while maintaining control over the polymerization.     

Gelation-free synthesis of poly(allyl methacrylate-co-butyl acrylate) copolymers by atom transfer radical polymerization

The preparation of functional copolymers based on allyl methacrylate (AMA) and butyl acrylate (BA) without gel formation via atom transfer radical polymerization is described. The gelation-free controlled radical copolymerizations were carried out in benzonitrile solution at 70 °C using ethyl 2-bromoisobutyrate as initiator and mixed halogen technique, copper chloride along with N,N,N′,N″,N″-pentamethyldiethylenetriamine as the catalyst system. Kinetic analyses have demonstrated that all the copolymerizations showed a general behaviour characterized by two clearly differentiated stages. Thus, in an initial stage, the polymerizations presented first order kinetic with respect to the monomer concentration. In the subsequent stage, at low-intermediate conversions, a deceleration in the rate copolymerization leads to limit conversions, which decrease as the initial concentration of BA in the feed increases. The reactivity ratios values were calculated from the copolymer composition determined by ¹H NMR, and using the extended Kelen–Tüdös method. Values of 2.70 ± 0.21 and 0.49 ± 0.04 were obtained for AMA and BA, respectively. The cumulative copolymer compositions as a function of conversion degree for the different monomer molar fractions in the feed showed gradient character of the copolymers obtained.     

Plasma polymerization of allyl alcohol on polyolefin-based materials: characterization and adhesion properties

Hydroxyl-rich surfaces have been obtained through the plasma polymerization of allyl alcohol on various polyolefin-based substrates. The influence of plasma parameters (deposition time and power), the type of substrate, and water washing on the chemical structure of the formed plasma polymers was investigated. The characterization involved contact angle measurements, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) analyses. To increase the sensitivity of XPS towards hydroxyl groups, derivatization with trifluoroacetic anhydride was performed. In addition, the adhesion between plasma-polymerized layers and a two-component polyurethane lacquer was evaluated by a 90° peel test. It was shown that power had a pronounced influence on both water wettability and hydroxyl group retention, while deposition time mainly influenced the film thickness. A relationship between the extent of hydroxyl functionality and the loss of material during the washing procedure was also found. Furthermore, it was shown that the chemical structure of the plasma polymers was not seriously affected by the choice of substrate. On the contrary, the adhesion properties of the substrates with plasma-polymerized layers were found to be highly dependent on the substrate used. For one of the substrates, the adhesion tests revealed an excellent lacquer adhesion when appropriate process parameters during the plasma deposition were used. The other substrate showed considerably lower peel forces. The difference in adhesion properties between the substrates may be explained as an effect of vacuum-ultraviolet (VUV) emission present during the plasma deposition. The VUV emission is able to create radicals in the near-surface region of the substrate and thereby cause chain scission reactions, lowering the cohesive strength of the substrate. Finally, this study showed that reflection absorption spectroscopy (RAS) is a suitable FTIR technique for obtaining structural information about plasma-polymerized layers thinner than 50 nm.     

丙烯酸酯单体对第2代丙烯酸酯结构胶性能的影响

在SGA(第2代丙烯酸酯结构胶)中引入不同的单体[如THFMA(甲基丙烯酸四氢呋喃酯)、LMA(甲基丙烯酸月桂酯)和MEMA(甲基丙烯酸甲氧基乙酯)等],并考察了不同单体对SGA的反应速率、断裂伸长率、耐湿热老化性能及不同基材粘接性能的影响。研究结果表明:不同单体的反应活性依次为MEMATHFMALMA;含不同单体之SGA的耐湿热老化性能、拉拔强度保持率及其对塑料基材的粘接强度依次为含MEMA之SGA含THFMA之SGA含LMA之SGA,断裂伸长率依次为含LMA之SGA含MEMA之SGA含THFMA之SGA,吸水率依次为含THFMA之SGA含MEMA之SGA含LMA之SGA。     

Photocuring and thermomechanical properties of multifunctional amide acrylate compositions derived from castor oil

The photopolymerization of multifunctional acrylate monomers synthesized from castor oil was investigated by photo-DSC. These studies revealed that the extent of photopolymerization depended on the double bond concentration and a greater degree of crosslinking occurred in monomer mixtures with higher difunctional content. The monomer mixtures displayed significantly higher maximum rate of polymerization (R_p^max) and shorter time to reach peak maximum than the pure monomers. DMTA studies of films showed good storage modulus and broad tan δ transitions indicating heterogeneity in the crosslinked networks. The films displayed sub-T_g transitions in the loss modulus curves were possibly due to the side chain motions of the monomer acrylates which increased with increasing triacrylate concentration. Glass transition temperature (T_g) of these networks depended on composition and shifted to higher values with increasing amount of triacrylate.     

相转移催化法制备丙烯酸烯丙酯

以丙烯酸钠与氯丙烯(ALC)为原料,在相转移催化剂存在下合成出丙烯酸烯丙酯(ALA)粗产品,经离心、干燥、蒸馏等纯化手段得ALA产品。最佳反应条件为:以四丁基溴化铵为相转移催化剂,用量为反应物物质的量的4%,VALC∶V水=1∶1,在40℃下反应1.75 h,ALA产率达94%以上,纯度达98%以上。     

The synthesis, spectroscopic and electrochemical properties, and application of new dyeing photoinitiator systems for acrylate monomers polymerization

New symmetrical bicationic polymethine dyes were synthesized and their spectroscopic and electrochemical properties were described. The bichromophoric dyes (benzothiazole, benzoxazole, indolinium derivatives) were investigated as sensitizers in the free radical photopolymerization initiated by their borate salts. The obtained kinetic results shown that bicationic polymethine dyes as the organoborate salts are much efficient photoinitiating systems of acrylate monomers polymerization than monocationic parent dyes. The rate of polymerization depends on ΔG_ET of electron transfer from borate anion to the excited singlet state of bicationic polymethine dye. The relationship between the rate of polymerization and the free energy of electron transfer process shows the dependence predicted by the classical theory of electron transfer.     

Preparation and properties of urethane/acrylate composite by emulsion polymerization technique

Aqueous polyurethane–acrylic hybrid emulsions were prepared by semibatch emulsion polymerization of a mixture of acrylic monomers (styrene, butyl acrylate and acrylic acid) in the presence of polyurethane dispersion. Equivalent physical blends were prepared by mixing acrylic emulsion and polyurethane dispersion. The weight ratio between acrylic and polyurethane components was varied to obtain enhanced performance properties and microphase structure of hybrid latexes. The synthesized emulsion hybrids and physical blends were characterized by fourier transform infrared spectroscopy, thermogravimetric analysis. The experimental results indicate better acrylic–polyurethane compatibility in hybrid emulsions than in physical blends, resulting in improved chemical and mechanical properties. The blend ratio 50:50% (w/w) exhibited synergistic effects between the two polymers and revealed remarkable improvement in various coating properties over other blend ratios and the individual resin components.     

Effect of chemical structure and preparation process on the aggregation structure and properties of polyimide film

In this article, polyimide (PI) films were fabricated via the three‐step method including the reactions of condensation polymerization, chemical imidization, and thermal imidization. In comparison with the conventional two‐step method to produce PI films, there was an additional step in the present method, i.e., chemical imidization. The aim of chemical imidization was to get PI intermediates with different pre‐imidization degree (pre‐ID). And PI component in PI intermediates acted as in‐situ rigid‐rod segments and induced orientation in the films of PI intermediates. Then the orientations of molecular chains were preserved in the following thermal imidization, and caused the difference in aggregation structure and property of the final PI films. The test results indicated that the orderly degree of molecular chains and mechanical properties of PI films increased with pre‐ID increasing. Furthermore, this tendency was much more obvious for more rigid backbone structure. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effect of external electric field on morphologies and properties of the cured epoxy and epoxy/acrylate systems

In this article, the influences of the external electric field exerted to the curing epoxy and epoxy/acrylate systems on their cured microstructures and macroscopic performances were investigated by means of morphological investigation and some characteristic analyses. Epoxy and epoxy/acrylate (an interpenetrating polymer network) systems were subjected to the action of the alternating electric field during the curing process. The changes in the nanolamellae microstructure in the cured epoxy and the nanoellipsoid microstructure in the cured epoxy/acrylate systems resulting from the electric field treatment were observed using atomic force microscopy. Dynamic mechanical analysis showed that the external electric field treatment made the low and high relaxation peaks shift to the lower and higher temperatures, respectively. Thermogravimetric analysis implied that the curing reactions of the epoxy systems with the aid of the external electric field resulted in some negative influences on their thermal stability. The dielectric measurements demonstrated that the electrical properties of the epoxy system for vacuum pressure impregnation insulation of the high-voltage electric machines could be much improved with the aid of the external electric field. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Controlling properties of acrylate/epoxy interpenetrating polymer networks by premature termination of radical polymerization of acrylate

An approach is presented to control properties of sequentially synthesized acrylate/epoxy interpenetrating polymer networks (IPNs) and is used to print uniform and graded properties. These IPNs are constructed by partial formation of the acrylate network, removal of the excess components, expansion with the epoxy system, and curing. The partial crosslinking of the initial network is controlled by photo polymerization and used to manipulate the final properties. The process is used to print homogeneous and graded IPNs with properties in the range of 10 to 1000 MPa. The curing of acrylate, the control mechanism, is studied by Fourier Transform Infrared Spectroscopy (FTIR) during curing on a temperature and environment controlled attenuated total reflection system. Fast scanning calorimetry is used to study network formation, nanoindentation is used to characterize local change of modulus, and uniaxial tensile testing is used to characterize stress response of the printed systems. POLYM. ENG. SCI., 59:1729–1738 2019. © 2019 Society of Plastics Engineers     

氧化锆对环氧丙烯酸酯乳液性能的影响

采用γ-氨丙基三乙氧基硅烷(KH-550)对氧化锆(ZrO2)纳米粒子进行表面处理,通过傅里叶变换红外光谱(FT-IR)和X射线衍射(XRD)对改性纳米氧化锆的结构进行了表征,采用扫描电镜(SEM)观察其形貌及分散性.利用改性后的氧化锆对环氧丙烯酸酯乳液进行改性,分析了不同氧化锆添加量的乳液薄膜的热稳定性,并以改性环氧...     

Influence of chemical polymerization conditions on the properties of polyaniline

The chemical polymerization of aniline in aqueous solutions was studied as a function of a wide variety of synthesis parameters, such as pH, relative concentration of reactants, polymerization temperature and time, etc. The polymer was synthesized using a number of different oxidizing agents and different protonic acids. It was found that the reaction yield was not sensitive to most variables. By contrast, the inherent viscosity of the polymer, measured in solutions in concentrated sulphuric acid, was strongly dependent on the synthesis parameters. Optimum reaction conditions are outlined for the chemical polymerization of aniline, for post-treatment with aqueous HCl solutions, and for compensation of the emeraldine salt into its base form. Under such conditions, high-quality polyaniline base was synthesized with an inherent viscosity (0.1% w/w polymer in sulphuric acid) as high as 2.32 dl g⁻¹.     

Anionic polymerization of methyl acrylate

The homogeneous polymerization of methyl acrylate in tetrahydrofuran using a variety of sodium aryl catalysts has been investigated at ?75°C and ?30°C. The mode of action of each catalyst is discussed and its efficiency in producing high polymer has been calculated from the yields and polymer characteristics. Sodium trityl is the most effective catalyst at both temperatures. Dilatometry has shown that with sodium naphthalene at ?70°C, rapid initial polymerization to about 10% conversion in 4 min is followed by a very low rate period which proceeds at low temperature for at least 24 h when conversions up to 50% have been observed. Throughout this period a species is present which absorbs at 320 nm and which is immediately lost on addition of a proton donor. There is evidence suggesting that this dormant form of the poly(methyl acrylate) anion is an oxyanion. It is postulated that carbanions are formed initially and are responsible for the rapid polymerization rate. They also isomerize in an equilibrium reaction to form the unreactive oxyanions. The rate of further propagation is thus controlled by the value of the equilibrium constant which in this system is strongly in favour of the oxyanions. On the basis of this mechanism some rate constants have been calculated.