Continuous thermal bulk copolymerization of styrene and maleic anhydride

Thermal bulk copolymerization of styrene (monomer 1) and maleic anhydride (monomer 2) was carried out in a continuous stirred tank reactor (CSTR) with a double helical ribbon-anchor impeller. A series of experimental runs under different operating conditions (average residence time, reaction temperature, and the composition in the inflow stream) were done, which showed that steady states could be approached. The effect of operating conditions on monomer conversion and copolymer composition was discussed. A CSTR model was established and the model parameters from the semicontinuous tests were used to predict conversions and copolymer compositions of the continuous process under transient and steady states. Kinetics from the semicontinuous bulk copolymerization were transferable to the continuous process. The modeling work for the continuous process showed that the same result as in a semicontinuous process could be obtained; the numerical method in which the gel effect on the copolymerization was incorporated exhibited excellent agreement between the model calculation and the experimental data. However, when using the assumption that k₂₂ = 0, k₂₁[M₁] ≫ k₁₂[M₂], (R_I/2k_t)^1/2 is a constant, and V is a constant, the predictions from the analytical solution to the model were in good agreement with the actual process data. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 615–622, 1999     

Grafting copolymerization of maleic anhydride onto styrene‐butadiene‐styrene block copolymer through solvothermal process

The grafting copolymerization of maleic anhydride (MAH) onto styrene‐butadiene‐styrene terpolymer (SBS) was carried out through a new synthesis method––solvothermal synthesis. Infrared (IR) spectra and solid state ¹³C‐NMR confirmed that maleic anhydride was successfully grafted onto the SBS backbone. The effects of different solvents, different initiators and their concentration, the amount of MAH, SBS concentration, and reaction time on the graft degree were evaluated, and the optimal conditions were obtained. Results indicated that the grafting reaction of MAH onto SBS through solvothermal method can be carried out in both good solvents and poor solvents, which are much different from the traditional solution grafting method, and high grafting degree can be obtained in good solvents. Finally, we also compared the grafting degree (GD) prepared by the solvothermal method with that by the melt grafting method and solution grafting method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5274–5279, 2006     

二釜串联连续本体法制备SMA

用二釜串联连续本体工艺制备苯乙烯-顺丁烯二酸酐无规共聚物,分别研究并获得了首釜和第二釜的启动操作策略和稳态工艺条件。     

Semicontinuous heterophase copolymerization of vinyl acetate and butyl acrylate

Vinyl acetate (VAc) and butyl acrylate (BuA) were copolymerized in heterophase by a semicontinuous process (unseeded) and compared with the seeded semicontinuous microemulsion polymerization of the same monomers. A mixture of sodium dodecyl sulfate (SDS) and poly(ethylene oxide) dodecyl ether (Brij‐35®) were used as surfactants. The effects of monomer addition rate (R_a) and surfactants concentrations (4 or 1 wt % with respect to the initial mixture of reaction) on polymer and latex properties were studied. High copolymer content latexes (24–36 wt %) with average particle diameters (D_p) from 38 to 55 nm and relatively narrow particle size distributions, high polymerization rates, weight ratios of polymer to surfactant (P/S) from 13.3 to 32.8 were obtained. The number‐average molecular weights (M_n) were between 96,000 and 188,000 g/mol. Homogeneous copolymer compositions were obtained throughout the reaction for both, seeded and unseeded processes, which is not possible by the usual batch microemulsion process. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Graft copolymerization of maleic anhydride onto low‐molecular‐weight polyisobutylene through solvothermal method

The free‐radical graft copolymerization of maleic anhydride (MAH) onto highly reactive low molecular weight polyisobutylene was conducted by the use of benzoyl peroxide as an initiator through the solvothermal method. Fourier transform infrared spectra and ¹H‐NMR spectra confirmed that maleic anhydride was successfully grafted onto highly reactive low molecular weight polyisobutylene backbone, and the grafting mechanism also was proposed. The effect of benzoyl peroxide content, MAH concentration, total reactant amount in the reaction vessels, reaction temperature and time, and different kinds and volumes of solvents on MAH's degree of grafting was investigated in detail. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

丁二烯本体聚合及与异戊二烯的共聚合

研究了负载钛催化剂引发丁二烯本体聚合合成高反式-1,4-聚丁二烯的条件,如催化剂组成、温度、时间、催化剂用量等对聚合过程和催化效率的影响.在Al/Ti摩尔比为70,30℃,8h条件下,在Ti/Bd(摩尔比)为(1～2)×10-5时,丁二烯的本体聚合具有最佳催化效率,聚丁二烯的反式-1,4-结构摩尔分数为99%.并对丁二烯和异戊二烯的共聚合进行了研究,结果表明二者发生了共聚合.     

Study on kinetics of copolymerization of styrene and maleic anhydride in methyl ethyl ketone

The compositional and rate data are measured for the alternating copolymerization of styrene and maleic anhydride in methyl ethyl ketone at 60°C with AIBN as initiator. The kinetic scheme is evaluated in terms of the participation of a monomer-monomer complex, accepting that the monomer radical at the chain end reacts only with the dissimilar monomer of the complex. r₁ and r₂ are determined for vanishing complex concentrations. r₂ is very low but not zero. The ratios of propagation via the complex to those of normal alternating propagation could be evaluated as well as the term 2?δ₁δ₂r₁r₂. The latter only for vanishing [M₁] or [M₂] respectively and for [M₁] = [M₂]. This allowed us to calculate the rate vs. composition curve for three constant overall monomer concentrations. For the lowest overall concentration the agreement between calculation and experiment is only fair, but for the overall concentrations [M₁] + [M₂] = 1 and 3 mol 1^?1 it is good, thus demonstrating the possibility of describing the polymerization process by the model used here. The concept of participation of charge transfer complex between styrene an maleic anhydride is found to explain most features of copolymerization of these monomers in methyl ethyl ketone.     

Study on controlled radical alternating copolymerization of styrene with maleic anhydride under UV irradiation

The copolymerization of styrene with maleic anhydride (MAh) in the presence of 1‐(ethoxycarbonyl)prop‐1‐yl dithiobenzoate was carried out under UV irradiation at room temperature, and showed ‘living’ polymerization nature which was evidenced by: linear evolution of molecular weight with conversion; and narrow molecular weight distribution (M_w/M_n = 1.08–1.20). The compositional analysis and the sequence structural information of the copolymer obtained from Distortionless Enhancement by Polarization Transfer (DEPT) NMR experiments demonstrated that the copolymers obtained possess strictly alternating structure. © 2003 Society of Chemical Industry     

SMA工业生产计量及分析方法

运用密度法建立了可用于苯乙烯－马来酸酐共聚物（SMA）工业生产听密度－温度－浓度关系式。应用表明，此式在工业生产计量仪表的标定中是可信和可靠的。利用工业生产获得了有关工艺参数，还建立了针对SMA生产的反应器方程式。经20d连续工业生产考察表明，用反应器方式式所预测的转化率与实际值非常吻合，该方程式具有指导SMA工业生产的意义。     

Copolymerization of styrene and maleic anhydride in supercritical carbon dioxide

The copolymerization of styrene (St) and maleic anhydride (MA) was carried out in supercritical carbon dioxide (SC CO₂). It was found that St and MA are easy to copolymerize in SC CO₂ and the conversion can reach 97%, and that very fine and dry powders are obtained. The products were characterized using Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). GPC data showed that the molecular weight of the copolymer reach 3.62 × 10⁴ g mol^?1. Scanning electron microphotographs showed the minimum particle size of the product is about 200 nm. DSC measurements indicated that the glass transition temperature (T_g) of the copolymer increases with increasing the MA content in the copolymer. TGA curve showed that the copolymers were decomposed at about 350°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

A kinetic study on bulk thermal polymerization of styrene

The kinetics of bulk thermal polymerization of styrene over the range of 100–200 °C has been studied based on three stage polymerization model (TSPM) in this paper. TSPM plots showed that the whole polymerization course only exhibits two stages, low conversion stage and gel effect stage, which is consistent with TSPM as the reaction temperature is higher than the glass transition temperature of polystyrene. It was found that the critical conversion, x₁, for the transition from low conversion stage to gel effect stage is independent of the reaction temperature and approximately equal to 0.5. In addition, the apparent reaction rate constants obtained from TSPM plots could be correlated to temperature by Arrhenius equation. Expressions predicting number-average molecular weight were also derived according to TSPM. Using the expressions to treat experimental data available in the literature, it was found that number-average molecular weight is independent of the conversion and relative to the reaction temperature at low conversion stage. However, it varies with the conversions at gel effect stage and the variations are more obvious as the reaction temperature rises.     

Microwave radiation copolymerization in solid state of maleic anhydride and allylthiourea

Microwave radiation copolymerization of maleic anhydride and allylthiourea was studied in solid state. Composition of the monomer feed and the power and time of microwave radiation on conversion and intrinsic viscosity were discussed. Reactivity ratios for maleic anhydride and allylthiourea were also determined. Values of r₁ and r₂ were 0.875 and 0.650 for maleic anhydride and allylthiourea, respectively. The copolymer can be used as soluble macromolecular complexing agents for metal ions. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1563–1566, 1998     

Miniemulsion and conventional emulsion copolymerization of styrene and butadiene: A comparative kinetic study

The kinetics of conventional and miniemulsion copolymerizations of styrene and butadiene were compared using the Mettler RC1 calorimeter. A two‐step homogenization procedure was applied to obtain miniemulsions of these monomers with hexadecane as the costabilizer. The results indicated that the miniemulsion polymerizations proceeded mainly by nucleation in the monomer droplets, while in the conventional emulsion polymerizations, particle formation occurred by a combination of micellar and homogeneous nucleation. The overall rate of miniemulsion polymerization was faster than the corresponding conventional emulsion system if the surfactant concentration was below the critical micelle concentration (cmc) and slower if the surfactant concentration was above the cmc. The homogenization process is important for making stable miniemulsion systems, but had no effect on the conventional emulsion system (without hexadecane), most likely because of the second stage addition of the butadiene monomer. The dependencies of the rate of polymerization (heat of reaction) and number of particles on the surfactant concentration differed for the two types of polymerization systems. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2304–2312, 2006     

Modification of LLDPE using esterified styrene maleic anhydride copolymer: Study of its properties and environmental degradability

Linear low‐density polyethylene (LLDPE) was blended with decanol‐esterified styrene maleic anhydride copolymer (MDESMA) with an aim to enhance the environmental degradability of polyethylenes. Styrene‐maleic anhydride copolymer (SMA) was synthesized by precipitation polymerization, using benzoyl peroxide (BPO) as initiator. SMA was esterified with a long‐chain monoalcohol, n‐decanol, using methyl ethyl ketone (MEK) as solvent at 80°C to obtain monoesterified styrene‐maleic anhydride (MDESMA). Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA) were performed to characterize SMA and MDESMA. IR spectra of MDESMA showed a decrease in intensity of peak responsible for carbonyl absorption of a five‐membered ring anhydride group along with broadening of carboxyl O? H stretching peak. TGA showed two‐stage degradation for SMA and MDESMA. LLDPE was blended with MDESMA in single‐screw extruder and blends were characterized thermally by DSC and TGA. A single endothermic melting peak of LLDPE/MDESMA blend was observed. Films of the blends, formed by compression molding, showed an increase in modulus of elasticity but a decrease in elongation at break with increasing concentration of MDESMA. LLDPE/MDESMA blend compositions when kept in phosphate/citric acid buffer solution (pH ～ 8) showed initial weight gain because of water absorption and subsequently loss in weight due to dissolution of soluble component of blends. Film samples of blends kept for soil burial also showed similar behavior. Contact‐angle measurement of film samples of the blends showed an increase in value on soil burial, indicating degradation/dissolution of MDESMA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 102–108, 2004     

Modeling of bulk copolymerization reactor using chain-length-dependent rate constants

A mathematical model is developed for a batch reactor in which binary free radical copolymerization occurs. The diffusion-controlled features of the propagation and termination reactions are taken into account by applying the free volume theory, whereas the chain-length-dependent termination rate constant is formulated by using the continuous probability function. Application of the pseudokinetic rate constant method, as well as the terminal model, reduces the complex rate expressions for the copolymerization system to those for the corresponding homopolymerization system. In addition, the moment equations of the living and dead polymer concentrations, as well as the equation for copolymer composition, are derived to compute the average molecular weight and the copolymer composition. The model is proven adequate when applied to the copolymerization system of styrene and acrylonitrile with AIBN(2,2′-azobisisobutyronitrile) initiator. The results of model prediction clearly show that even the propagation reaction is limited by the diffusion of monomers at higher conversion and that the azeotropic fraction of styrene is about 0.6. It is noticed that as the monomer conversion increases, the molecular weight distribution tends to become broader because the weight-average molecular weight increases at a faster rate than the number-average molecular weight. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1015–1027, 1997     

马来酸酐/苯乙烯多单体接枝低等规聚丙烯

低等规聚丙烯（LIPP）是由等规立构和间规立构组成的嵌段共聚物，具有低的结晶性能，良好的粘接性和加工性能，在胶粘剂领域有着广阔的应用前景。然而LIPP的非极性和低的机械性能限制了它的应用。本文采用溶液法，以过氧化二异丙本（DCP）为引发剂，以苯乙烯（St)作为共聚单体，将马来酸酐（MAH）接枝到低等规聚丙烯（LIPP）大分子链上，采用化学滴定法测定产物（LIPP－g-MAH-St)的接枝率（GR），并系统地研究了加料方式，单体用量，引发剂用量，反应时间等因素对GR的影响，结果表明，采用先加入引发剂的加料方式有利于马来酸酐对低等规聚丙烯的接枝反应，反应的最佳条件是：反应时间7h，MAH的加入量为9份（以100份LIPP计），引发剂DCP的加入量为0．45份。     

马来酸酐溶液法接枝改性天然橡胶的研究

采用溶液法，选用极性单体马来酸酐(MAH)，在非隔氧条件下，以过氧化苯甲酰(BPO)为引发剂对天然橡胶(NR)进行接枝改性。通过傅立叶红外光谱对接枝物进行定性表征；采用化学滴定法测定了反应产物的接枝率和接枝效率；详细讨论了反应单体和引发剂的用量、反应时间等因素对反应产物接枝率和接枝效率的影响；并应用正交设计法评价了各因素对产物接枝率和接枝效率的影响。     

Blends of acrylonitrile–butadiene–styrene/waste poly(ethylene terephthalate) compatibilized by styrene maleic anhydride

Waste poly(ethylene terephthalate) (PET) from thin bottles was blended with acrylonitrile–butadiene–styrene (ABS) copolymer in different proportions, up to 10 wt %. Styrene maleic anhydride (SMA) copolymer was used as a compatibilizer. The tensile strength and heat deflection temperature of the blend were higher than that of virgin ABS. Flexural modulus remained unaffected, although a slight decrease in impact property was observed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2593–2599, 2001     

Effect of comonomer composition on the controlled free-radical copolymerization of styrene and maleic anhydride by reversible addition-fragmentation chain transfer (RAFT)

Controlled free-radical copolymerization of styrene and maleic anhydride was performed in 1,4-dioxane or tetrahydrofurane solution at 60 °C using the RAFT technique. The effect of monomer feed ratio on copolymerization kinetics and on control over molar mass distribution was examined. It was shown that polymerization was faster and quality of control was poorer when the proportion of maleic anhydride in the monomer feed was larger. These features were assigned to a decrease in the chain transfer constant of the polymeric RAFT agent, most probably due to an increase in the apparent rate constant of propagation with the proportion of maleic anhydride.