Methyl acrylate/N-phenylmaleimide copolymers, 1. Synthesis of copolymers and effect of copolymer composition on huggins constant KH

This paper deals with the synthesis of methyl acrylate/N-phenylmaleimide copolymers having different compositions, (mole fractions of N-phenylmaleimide for the four copolymers MP-1, MP-2, MP-3, and MP-4 are 0.0664, 0.3905 and 0.5445, respectively) by free radical solution polymerization in cyclohexanone using azoisobutyronitrile as an initiator. The compositions of the copolymers have been determined by elemental analysis. The variation of the Huggins constant K_H with composition for the copolymers in three solvents, methyl ethyl ketone, dimethylformamide and cyclohexanone is described. K_H is found to be dependent both on solvent and composition of the copolymers.     

Effect of copolymer composition on the miscibility of blends of styrene-acrylonitrile copolymers with poly (methyl methacrylate)

The phase behaviour for blends of various polymethacrylates with styrene-acrylonitrile (SAN) copolymers has been examined as a function of the acrylonitrile content of the copolymer. Poly(methyl methacrylate), poly(ethyl methacrylate) and poly(n-propyl methacrylate) were found to be miscible with SANs over a limited window of acrylonitrile contents while no SANs appear to be miscible with poly(isopropyl methacrylate) or poly(n-butyl methacrylate). These conclusions were reached on the basis of lower critical solution temperature (LCST) and glass transition temperature behaviour. All miscible blends exhibited phase separation on heating, LCST behaviour, at temperatures which varied greatly with copolymer composition. An optimum acrylonitrile (AN) level ranging from about 10 to 14% by weight resulted in the highest temperatures for phase separation which has important implications for selection of SANs to produce homogeneous mixtures by melt processing. The basis for miscibility in these systems is evidently repulsion between styrene and acrylonitrile units in the copolymer as explained by recent models. The excess volumes for all blends are zero within experimental accuracy which suggests that the interactions for miscibility are relatively weak even for the optimum AN level. This interaction becomes smaller the larger or more bulky is the alkyl side group of the polymethacrylate.     

Effect of structure and composition on physico-mechanical properties of methyl methacrylate/alkyl (meth)acrylate copolymers

The paper describes the fabrication of cast acrylic sheets by copolymerizing a prepolymer syrup of methyl methacrylate (MMA) with varying amounts (1-20 wt.-%) of 2-ethylhexyl methacrylate (EHMA), n-hexyl methacrylate (HMA), 2-ethylhexyl acrylate (EHA) and n-hexyl acrylate (HA). The effect of structure of copolymer on light transmittance, density and mechanical properties was evaluated. Tensile strength and storage modulus decreased with increasing comonomer content. Strain increased significantly in the case of MMA/EHA and MMA/HA copolymer sheets having 15 and 20 wt.-% of comonomer. Softening temperature of copolymer samples was determined using dynamic mechanical thermal analysis. Heat deflection temperature under flexural load and softening temperature decreased with increasing comonomer content in copolymer.     

苯乙烯和甲基丙烯酸甲酯梯度共聚物的应用

将用原子转移自由基聚合及连续补加甲基丙烯酸甲酯（MMA）的方法制备的苯乙烯（St）/MMA梯度聚合物P（Pt-t-MMA）作为增容剂应用于聚氯乙烯/苯乙烯-丁二烯-苯乙烯嵌段共聚物（PVC/SBS）和PS/PMMA聚合物合金的增容和改性。扫描电镜结果表明,P（St-t-MMA）可以改善PVC/SBS和PMMA/PS合金的相容性。PVC/SBS合金中加入少量P（St-t-MMA)后,冲击强度从6.0kJ/m^2提高到12.1kJ/m^2,加工流变性能得到了改善。SBS用量也影响PVC/SBS合金的冲击强度。     

苯乙烯和甲基丙烯酸甲酯梯度共聚物的合成

以2－溴异丁酸乙酯为引发剂,溴化亚酮／联二吡啶／铜为催化剂,通过原子转移自由基聚合（ATRP）以及连续补加第二单体的方法制备苯乙烯（St)－甲基丙烯酸甲酯（MMA）梯度共聚物。共聚物相对分子质量的可控性和窄分布证明这是一种活性聚合过程,反应过程中聚合物链的组成变化情况说明形成了梯度结构;聚合温度和MMA加料速度影响聚合速率和共聚物梯度结构,聚合温度升高和加料速度增大使聚合速率加快;改变单体与引发剂的配比,可以得到相应的相对分子质量聚合物。     

Terpolymerization with depropagation: Modelling the copolymer composition of the methyl methacrylate/alpha-methylstyrene/butyl acrylate system

The kinetics of the free radical terpolymer system methyl methacrylate (MMA)/alpha methyl styrene (AMS)/butyl acrylate (BA) have been studied in detail. Previous work with terpolymer systems typically has not involved monomers or cases where depropagation was a significant concern and hence the Alfrey-Goldfinger model was adequate to describe the system. In other works involving the MMA/AMS/BA system, modelling of the kinetics has not been attempted. In order to properly study this system, a new model has been developed based upon some of the underlying principles of the binary Kruger model (Kruger et al., 1987. Ein modell zur beschreibung reversibler copolymerisationen. Makromolecular Chemie, 188, 2163-2175.). A sensitivity analysis and benchmarking of the new model has been done and the terpolymerization system has been studied at for selective feed ratios with promising results.     

N-苯基马来酰亚胺/甲基丙烯酸甲酯/苯乙烯三元共聚物对PVC的改性

研究了N-苯基马来酰亚胺/甲基丙烯酸甲酯/苯乙烯三元共聚物(简称三元共聚物)对PVC力学性能、耐热性和加工性能的影响。结果表明:随着三元共聚物用量的增加,试样的拉伸性能、弯曲性能和维卡软化温度增加,但冲击强度有所下降;PVC共混料的熔融黏度降低,加工性能提高,但塑化时间延长。     

Kinetic Treatment for copolymerization of styrene or methyl methacrylate with N-phenylmaleimide

Shirota‘s kinetic model and our kinetic model were used to treat the kinetic data of styrene (St) and N-phenylmaleimide (PMI) copolymerization in which chaxge-transfer complex (CTC) was formed. The results obtained by Shirota‘s kinetic model were disagreed with the experiments and the experimental phenomena could not be explained. The kinetic data of all feed fractions can be treated with our kinetic model, and the experimental phenomena can be explained from the propagation constants and reactivity ratios. Our kinetic model is also suitable for the kinetic data of methyl methacrylate (MMA) and PMI copolymerization in which CTC can not be formed.     

Preparation and characterization of copolymers from methyl methacrylate and cardanyl methacrylate

Copolymers of methyl methacrylate (MMA) and cardanyl methacrylate (CMA) were synthesized, characterized and their physico-mechanical properties were investigated. The benzoyl peroxide-initiated copolymerization was carried out by using different mole fractions of CMA (0.02–0.10) in the initial feed at 80°C. Structural characterization of copolymers was done using FTIR and ¹H NMR spectroscopic techniques. The thermal stability of the copolymers was evaluated using dynamic thermogravimetry. Incorporation of CMA in the MMA backbone leads to an improvement in thermal stability.     

Poly(acrylonitrile‐co‐methyl acrylate) copolymers: Correlation between copolymer composition,morphology and positron annihilation lifetime parameters

A series of poly(acrylonitrile‐co‐methyl acrylate) copolymers of differing copolymer compositions are synthesized through free radical emulsion copolymerisation of methyl acrylate (MA) and acrylonitrile (AN) and by variation of the monomer feed ratios. The copolymers are characterized by NMR, SEC, WAXD, DMA, and positron annihilation lifetime spectroscopy. Results show that, there is a linear decrease in the glass transition temperature (T_g) of the copolymers and the MA content. There is also a progressive decrease in the crystallinity of the copolymers with increasing MA content. Positron results show a sigmoidal variation in the ortho positronium lifetime with an increasing MA content. The low MA content, semi‐crystalline copolymers show a positive deviation from the linear additive relationship between the o‐Ps lifetime and MA content, whereas the higher MA content amorphous copolymers show a negative deviation from the linear additive behavior. The o‐PS intensity shows a linear behavior with MA content with a slight deviation from the additive linear behavior for the very high‐content MA copolymer. These variations in the measured positron lifetime parameters are interpreted in terms of the copolymer morphology. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and properties of alkoxysilane/butyl acrylate/methyl methacrylate copolymer latices

The incorporation of alkoxysilanes into latex systems is of major interest in the field of colloidal science. Two kinds of vinyl‐containing alkoxysilanes, methacyloxypropyltrimethoxyl silane and vinyltriethoxysilane, were copolymerized with butyl acrylate and methyl methacrylate by seeded emulsion polymerization, and copolymer latices were obtained. The morphologies of the latex particles were characterized with transmission electron microscopy. Dynamic light scattering showed that the particle size increased and the particle size distributions of all the copolymer latex particles were alike with increasing amounts of organosilane. The effects of the organosilane content on the morphology of the particles, the rheology, and the swelling properties were also investigated. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and applications of the tertiary copolymer poly(ethylene glycol) methacrylate/methyl methacrylate/diethyl allylphosphonate

A novel poly(acrylonitrile‐co‐butadiene‐co‐styrene) (ABS) antistatic and flame‐retardant agent, poly(ethylene glycol) methacrylate/methyl methacrylate/diethyl allylphosphonate (PMMD), was synthesized from poly(ethylene glycol) methacrylate, methyl methacrylate, and diethyl allylphosphonate by free‐radical precipitation polymerization in the aqueous phase to improve the antistatic and flame‐retardant performance at the same time. Through adjustments of the molar ratios of the three monomers, various antistatic, flame‐retardant copolymers (PMMD) were synthesized. The molecular structure and thermal stability of PMMD were analyzed with Fourier transform infrared spectroscopy and thermogravimetric analysis. The electrical resistivity and flame‐retardant and mechanical properties of the ABS/PMMD composites were analyzed by a ZC90 megohmmeter, an oxygen index meter, a vertical burning tester, a memory impact testing machine, and a tensile testing machine. The morphology of PMMD in the ABS blends was characterized with scanning electron microscopy. The compatibilities of PMMD and ABS were characterized by the calculation of the thermodynamic work of adhesion via the measurement of the contact angle. The results show that the antistatic and flame‐retardant performance of ABS were greatly improved by the PMMD copolymer and the mechanical properties of ABS showed little reduction. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44126.     

Synthesis and characterization of N‐acryloylcarbazole/methyl methacrylate copolymers

Copolymers of N‐acryloylcarbazole (A) and methyl methacrylate (M) were synthesized in different in‐feed ratios. The composition of the copolymer was determined by the help of ¹H NMR spectrum. The comonomer reactivity ratios determined by Kelen‐Tudos (KT) and nonlinear error‐in‐variables methods were r_A = 1.12 ± 0.16, r_M = 0.94 ± 0.14, and r_A = 1.05, r_M = 0.90, respectively. Complete spectral assignments of the ¹H and ¹³C ¹H NMR spectra of the copolymers were done by the help of distortionless enhancement by polarization transfer (DEPT) and two‐dimensional NMR techniques, such as heteronuclear single quantum coherence (HSQC), total correlation spectroscopy (TOCSY), and heteronuclear multiple bond correlation (HMBC). The methine, α‐methyl, and carbonyl carbon resonances were found to be sequence sensitive. The signals obtained were broad because of the restricted rotation of bulky carbazole group and the quadrupolar effect of nitrogen present in carbazole moiety. Glass transition temperatures (T_g) were determined by differential scanning calorimetry and were found to be characteristic of copolymer composition. As the N‐acryloylcarbazole content increases, the T_g increases from 378.3 K for poly(methyl methacrylate) to 430.4 K for poly(N‐acryloylcarbazole). Variation in T_g with the copolymer composition were found to be in good agreement with theoretical values obtained from Johnston and Barton equations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2667–2676, 2006     

Mechanical properties and water vapor permeation of vinyltriethoxysilane/methyl methacrylate copolymers

Methyl methacrylate (MMA) was copolymerized with vinyltriethoxysilane (VTES) using ⁶⁰Co-γ-radiation at varying volume fractions of the liquid monomers in the feed. Thin copolymer films were prepared by casting tetrahydrofuran solutions of the copolymers on a mercury surface. The effect of the mole fraction of VTES in the copolymer on the glass transition temperatures, mechanical properties and water vapor permeabilities were investigated. Glass transition temperatures and mechanical properties decreased with increasing VTES content in the copolymer. However, the water vapor permeabilities were found to increase with the VTES content. The increased water vapor permeation was attributed to increased water solubility in the copolymers due to the presence of Si-O-bonds.     

Sequencing of methyl methacrylate/vinylidene chloride copolymers by NMR spectroscopy

Methyl methacrylate/vinylidene chloride (M/V) copolymers of different monomer concentrations were prepared by photopolymerization using the uranyl ion as photosensitizer. The copolymer composition was determined by chlorine estimation of the copolymers. The complete assignment of the ¹³C{¹H} NMR spectra of these copolymers is made by comparison with the spectra of poly(methyl methacrylate) and observing the changes in the intensities of the resonances with copolymer composition. The quaternary carbon of V- and M- center resonances were used for determining the sequence in terms of the distribution of V- and M- centered triads. The triad fractions thus obtained were compared with theoretically determined triad concentrations. The Monte Carlo simulation method was also used for estimating the copolymerization behavior. The variation of V- and M- centered triad concentrations was reported as a function of fractional conversions. The comonomer reactivity ratios, determined by both Kelen Tudos and nonlinear error in variables methods are r_V = 0.26 ± 0.04 and r_M = 2.88 ± 0.23. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 373–381, 1998     

On the effect of macromolecular composition and drug loading on thermal and tensile mechanical properties of methyl methacrylate and butyl methacrylate copolymers

In the last years, drug-eluting stents (DES) were considered as an important biomedical technology for cardiovascular intervention. In these devices, a thin polymer coating covers the metallic structure, aiming at the release of one or more active principles with controlled delivery kinetics. During DES implantation, structural failures on the thin coating may occur because of the mechanical expansion of the structure. The presence of a drug in the polymer matrix could severely influence mechanical properties, thus a mechanical characterisation of polymers and drug-loaded matrices results fundamental. To characterise a material produced for the manufacturing of drug-loaded coatings for DES, in the present work the thermomechanical analysis of an acrylic copolymer loaded with a drug is proposed. Obtained results showed that macromolecular composition could be varied to obtain the desired mechanical compliance; in addition, the drug can act as plasticiser. The present study would underline that it is possible to control mechanical properties by synthesising a tailored copolymer; furthermore, the importance of the study of the final system is fundamental when a polymer is considered as potential candidate to obtain coatings for DES.     

Optical and thermal properties of methyl methacrylate and pentafluorophenyl methacrylate copolymer: Design of copolymers for low-loss optical fibers for gigabit in-home communications

As a novel base material for low-loss graded index plastic optical fibers (GI POFs) in gigabit home networks, a copolymer of methyl methacrylate (MMA) and pentafluorophenyl methacrylate (PFPMA) was prepared and its thermal and optical properties were investigated. When the PFPMA content in the monomer feed was 0-50 mol%, both the glass transition temperature (T_g) and the decomposition temperature of the copolymer were higher than that for PMMA, which is the base material for many commercially available POFs. The transmittance of the copolymer was also found to be higher than that of PMMA since it has fewer C-H bonds per unit volume. As the core material of GI POFs, MMA-co-PFPMA (65/35 mol%), which had the highest T_g of 118 °C was utilized. A low-loss GI POF with an attenuation of 172-185 dB/km at the emission wavelengths of a high-speed light source (670-680 nm) was successfully obtained for the first time.     

Different composition poly(methyl methacrylate-co-butyl methacrylate) copolymers through seeded semi-batch emulsion polymerization

In the present work the synthesis and the chemical and thermal characterization of poly(methyl methacrylate-co-butyl methacrylate) copolymer, in three different macromolecular compositions, are reported. The aim of the present work was the identification of a standard method to obtain copolymers with controlled macromolecular composition, molecular weights and particle size distribution, together with the identification of the effect of the macromolecular composition on the material properties. A monomer-starved seeded semi-batch emulsion reaction was carried out and optimized, monitoring the kinetic of the copolymerization through the evaluation of residual monomer amounts. Then, an evaluation of the macromolecular composition was performed by Fourier transform infrared spectroscopy analysis. Molecular weight, molecular weight distribution, latex characteristics and thermal behaviour were also investigated.