Radical Copolymerization Of Methyl Methacrylate Research Articles

Varying the sequence distribution and hydrogen bonding strength provides highly Heat-Resistant PMMA copolymers

In this study we used free radical copolymerization of methyl methacrylate (MMA) and N-hydroxyphenylmaleimide (HPMI) to synthesize various poly(methyl methacrylate–co–N-hydroxyphenylmaleimide) (PMMA-co-PHPMI) random copolymers possessing high glass transition temperatures (Tg). FTIR and NMR spectroscopy, mass spectrometry, and differential scanning calorimetry (DSC) confirmed the chemical structures, thermal properties, hydrogen bonding interactions, and sequence distributions of these random copolymers. Because the reactivity ratio of MMA and HPMI is very different from that of MMA and maleic anhydride (MA), which prefer to form homopolymers, here we obtained partially alternating copolymers featuring strong intermolecular hydrogen bonding between the PMMA and PHPMI segments, resulting in the value of Tg increasing by up to 90 °C relative to that of the pure PMMA homopolymer. In addition, solid state NMR spectra revealed single values for the proton spin–lattice relaxation time in the rotating frame [T1ρ(H)] over all compositions of these random copolymers, with the relaxation times being shorter than the predicted average, indicating that the free volume had decreased and that the copolymers possessed rigid structures with high values of Tg.

Acrylic resins with oxetane pendant groups for free radical and cationic dual-curing photoresists

Photoresists play an important role in the electronic information industry; however, traditional photoresists have disadvantages including severe volume shrinkage, low precision, and poor adhesion. Here, a combined free radical / cationic dual-curing dry film photoresists (DFRs) for 405 nm photolithography was developed based on functional acrylic resins containing oxetane pendant groups. The acrylic resins were successfully synthesized by free radical copolymerization of methyl methacrylate, methacrylic acid, ethyl methacrylate and 3-ethyl-3-(methacryloyloxy)methyloxetane. The structure and properties of resins were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, gel permeation chromatography, differential scanning calorimetry and thermogravimetric analysis. The resins could undergo cationic photopolymerization to generate a film with good mechanical and thermal properties. Notably, the prepared DFRs showed excellent comprehensive performances including outstanding pattern transfer ability with a high resolution of 20 μm, high photosensitivity, high contrast, satisfactory developing speed, and good adhesion to the substrate. Such oxetane-containing acrylic resins may have potential application in high-performance DFRs.

Kinetic Study of the Free Radical Copolymerization of Methyl Methacrylate with 2-Perfluorooctyl Ethyl Methacrylate by Quantum Computational Approach

Fluorinated copolymers with perfluoroalkyl side chains have widespread use in applications requiring superior technology due to their unique surface properties. Kinetic analysis of copolymerization of fluorinated acrylates with conventional acrylates is necessary to synthesize such copolymers efficiently. However, kinetic investigation of such reactions are limited in the literature due to the experimental difficulties. In this study, the kinetic of copolymerization of methyl methacrylate with 2-perfluorooctyl ethyl methacrylate in toluene medium using AIBN initiator was investigated using quantum chemistry postulates as an alternative to experimental methods. Reaction rate constants (kp) for propagation were determined using transition state theory. A terminal effect models were used to examine four different addition reactions involving monomeric and dimeric radicals and monomers for both self- and cross-propagation. Reactant and product conformations were optimized with a DFT method using PBE0 function. The Evans-Polanyi relationship was used to calculate the rate of self- and cross-propagation of monomers. The results showed that the reactivity ratio of 2-perfluorooctyl ethyl methacrylate was found to be higher than that of methyl methacrylate. In addition, it was observed that the reaction conditions caused the random polymer structure due to the different rate constants in self and cross propagation.

Backbone-Degradable Polymers via Radical Copolymerizations of Pentafluorophenyl Methacrylate with Cyclic Ketene Acetal: Pendant Modification and Efficient Degradation by Alternating-Rich Sequence.

This work deals with syntheses of backbone-degradable polymers via the radical copolymerization of pentafluorophenyl methacrylate (PFMA) with 5,6-benzo-2-methylene-1,3-dioxepane (BMDO), which undergoes ring-opening propagation to afford an ester-bonded backbone. The combination of the electron-deficient methacrylate with the electron-rich cyclic monomer allowed high crossover copolymerization, and the electronic effect was clarified by the comparison with the copolymerization of methyl methacrylate (MMA) and BMDO. The PFMA units of the resultant copolymer underwent quantitative alcoholysis or aminolysis transformation into methacrylate or methacrylamide units along with the pendant functionalization. The alternating-rich sequence was achieved by feeding an excess ratio of BMDO, which was supported by MALDI-TOF-MS of the copolymer obtained by the RAFT copolymerization. The methanolysis-transformed copolymer carrying MMA units was decomposed under basic condition, and the degradation efficiency was superior to that of the copolymer obtained via radical copolymerization of MMA with BMDO because of the alternating-rich sequence.

Facile fabrication of superhydrophobic nanocomposite coating using modified silica nanoparticles and non-fluorinated acrylic copolymer

A superhydrophobic nanocomposite coating was fabricated using a simple procedure. The nanocomposite is composed of an acrylic copolymer and modified silica nanoparticles. The acrylic copolymer was prepared by free radical copolymerization of methyl methacrylate and dodeycl methacrylate monomers. Silica nanoparticles were synthesized and modified with an alkyl silane reagent, hexadecyltrimethoxysilane. A mixture of acrylic copolymer and modified silica nanoparticles, dispersed in dichloromethane, was then sprayed on glass and filter paper surface. Chemical composition and structure of the coatings were investigated by FTIR, FESEM, AFM, 1H-NMR and GPC. The wettability of the prepared coating was examined by water contact angle measurement. The results showed that superhydrophobic surfaces with contact angle above 150° and rough structures were obtained. The prepared coatings also exhibited superoleophilic and self-cleaning properties.

Specific features of radical copolymerization of methyl methacrylate and n-butyl acrylate in the presence of the tributylborane–p-quinone system

Copolymerization of methyl methacrylate (MMA) and n-butyl acrylate (n-BA) in the presence of the tributylborane–p-quinone system has been investigated. Reactivity ratios of the monomers differ from the values known for conventional radical polymerization. The copolymerization proceeds in a controlled manner according to the reversible inhibition mechanism. The nature of p-quinone and the composition of the monomer mixture affect the realization of this mechanism. The microstructure of the copolymers obtained in the presence of borane and p-quinones depends on the nature of the latter.

Free radical copolymerization of methyl methacrylate and N-2-methyl-4-nitro-phenylmaleimide: Improvement in the Tg of PMMA

In this investigation, a series of novel poly(methyl methacrylate-co-N-2-methyl-4-nitrophenylmaleimide) (PMMA-co-MI) copolymers possessing high glass transition temperatures (Tg) and high transparency was prepared through free radical polymerization. The resultant copolymers were characterized by spectroscopic techniques, elemental analysis, X-ray diffraction, and thermal methods. The PMMA-co-MI copolymers demonstrate higher thermal stability as compared to pristine PMMA. The Tg of copolymers is about 40 °C more than for PMMA. The copolymer composition has been determined by elemental analysis and 1H-NMR. The investigated copolymers show excellent solubility in wide range of organic solvents.

Radical Copolymerization Mediated by Unsaturated Metal Sites in Coordination Nanochannels.

Radical copolymerization of methyl methacrylate (MMA) and styrene was performed in [Tb(1,3,5-benzenetrisbenzoate)]n with coordinatively unsaturated metal sites (UMS) immobilized along the one-dimensional nanochannels. A drastic increase in the proportion of MMA units in the resulting copolymers was obtained compared with that obtained from the corresponding solution polymerization systems. Simultaneous coordination of MMA to the UMS is the key to increasing the MMA proportion during the copolymerization in the nanochannels, which was demonstrated by variable temperature IR measurements and several controlled experiments.

Aluminum pigments encapsulated with hybrid silica film with carboxyl groups and their stability and dispersibility in aqueous media

Aluminum pigments encapsulated with hybrid SiO2 film with carboxyl (–COOH) groups were prepared through a sol‐gel process of tetraethoxysilane (TEOS) and vinyl triethoxysilane (VTES), followed by radical copolymerization of methyl methacrylate (MMA) and acrylic acid (AA) with the vinyl group of VTES. The composite aluminum pigments were characterized by means of Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X‐ray photoelectron spectroscopy (XPS). Their stability in acid media as well as dispersibility in water were also evaluated. It was found that VTES and TEOS could simultaneously hydrolyze and condense with hydroxyl groups on the surface of aluminum particles to form inorganic‐organic hybrid films, and copolymerization of MMA and AA could provide the film surface with –COOH groups. This helps the composite aluminum pigments disperse better in water than raw aluminum pigments (raw Al) counterparts. Compared with the serious corrosion problem of raw Al, which generated about 113 mL H2 in acid media of pH=1 in 30 days, the composite aluminum pigments showed much better anticorrosion performance (with only about 0.5 mL H2). The waterborne coatings made with this composite aluminum pigments showed great improvements on adhesive performance and stability in 0.1 mol/L H2SO4 or NaOH media.

Kinetic modeling of atom transfer radical copolymerization of methyl methacrylate and 2‐(trimethylsilyl) ethyl methacrylate in a train of continuous stirred‐tank reactors

A comprehensive model was developed using the method of moments to describe the atom transfer radical copolymerization (ATRcoP) of methyl methacrylate and 2‐(trimethylsilyl) ethyl methacrylate in a train of continuous stirred‐tank reactors (CSTRs). The use of a train of CSTRs effectively decreases the residence time distribution and molecular weight distribution. Two different constraint conditions (i.e., constant feeding flow rate and constant total average residence time) were simulated. At constant feeding flow rate, the monomer conversion and average molecular weight are significantly improved by increasing the number of CSTRs in the train. Moreover, a constant total average residence time increases the productivity of copolymers with the increase in the number of CSTRs in the series. Thus, a train of CSTRs can be used to produce copolymers continuously with consistent quality. This method is important in obtaining a balance between the quality and quantity of the copolymer production for ATRcoP. POLYM. ENG. SCI., 55:1030–1038, 2015. © 2014 Society of Plastics Engineers

Reversible addition-fragmentation chain transfer copolymerization of methyl methacrylate and methyl acrylate

Pseudo-living radical copolymerization of methyl methacrylate and methyl acrylate under reversible addition-fragmentation chain transfer in a mass in the presence of reversible chain transfer agents of different nature was implemented. A comparison of physical and mechanical properties of narrowly dispersed copolymers was performed as well as copolymers obtained by uncontrolled radical polymerization.

Improved kinetic Monte Carlo simulation of chemical composition-chain length distributions in polymerization processes

Composite binary trees are introduced for an improved kinetic Monte Carlo (kMC) calculation of chemical composition-chain length distributions (CC-CLDs) in polymerization processes, such as the bivariate copolymer composition-CLD (CoC-CLD). For the calculation of the CC-CLD, each leaf node of the main tree, which reflects the number of macromolecules with a given chain length, serves as a root node for a sub-tree containing information on the CC distribution for the macromolecules with the selected chain length. For low maximum chain lengths of 1000, the improvement consists already in a reduction of the kMC operations by a factor between 103 and 106. The approach is illustrated for the calculation of the CoC-CLD in free and atom transfer radical copolymerization of methyl methacrylate and styrene while accounting for potential diffusional limitations. Main focus is on the capability of the algorithm to ensure an accurate calculation of the average copolymer composition including high chain lengths.

Hollow mesoporous silica nanoparticles modified with coumarin‐containing copolymer for photo‐modulated loading and releasing guest molecule

ABSTRACTHollow mesoporous silica nanoparticles (HMSNs) grafted with a photo‐responsive copolymer containing coumarin groups were successfully prepared. With uniform polystyrene nanoparticles and cetyltrimethylammonium bromide correspondingly as the template of core and channel, HMSNs were made from tetraethyloxysilane in alkalic condition. Epoxy groups were introduced onto the outer surface of HMSNs with γ‐(2,3‐epoxypropoxy)propyltrimethoxysilane and converted into azido groups with sodium azide, resulting in azido‐functionalized HMSNs (azido‐HMSNs). Meanwhile, single‐electron transfer‐living radical copolymerization of methyl methacrylate (MMA) and 7‐(2‐methacryloyloxy)‐4‐methylcoumarin (CMA) with propargyl 2‐bromoisobutyrate as the initiator produced alkynyl‐capped P(MMA‐co‐CMA) [alkynyl‐P(MMA‐co‐CMA)]. Finally, photo‐responsive HMSNs grafted with P(MMA‐co‐CMA) [HMSN‐g‐P(MMA‐co‐CMA)] was achieved through the click reaction between azido‐HMSNs and alkynyl‐P(MMA‐co‐CMA). Different techniques such as transmission electron microscopy, Fourier transform infrared spectroscopy, and thermal gravimetric analysis confirmed the successful preparation of the resultant hybrid nanoparticles and their intermediates. Because of its hollow core, mesoporous shell channels and light responsiveness, the coumarin‐modified HMSNs would be an interesting nano‐vehicle for guest molecules. Thus, the loading and release of pyrene with HMSN‐g‐P(MMA‐co‐CMA) was studied. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3791–3799

Effective dispersion of fullerene with methacrylate copolymer in organic solvent and poly(methyl methacrylate)

Dispersion of fullerene, C60, by addition of polymethacrylate dispersant in methyl methacrylate (MMA) and incorporation of C60 into poly(methyl methacrylate) (PMMA) were investigated. Copolymers synthesized by radical copolymerization of MMA and 2-naphthyl methacrylate (NMA), poly(MMA-co-NMA), effectively dispersed C60 in MMA to form clusters of 20 nm. In these cases, addition of minimal 110 naphthyl groups per unit C60 molecule afforded to give clusters with minimum of 20 nm sizes. Furthermore, block copolymers, poly(MMA-b-NMA) with MMA/NMA mole ratio from 12:1 to 20:1, also efficiently dispersed C60 to give formation of clusters of 20 nm size by addition of minimal 40 naphthyl groups per unit C60 molecule, which was corresponding to approximate nine layers of naphthyl group in block copolymer adsorbed on the surface of the cluster. Hybrid films of C60/PMMA, prepared by casting of C60-dispersed solution containing PMMA, exhibited absorbance at 400 nm linearly increased with C60 content.

Preparation and Characterization of Elastomers Based on Polydimethylsiloxane/Poly(methyl methacrylate) Blends

Polydimethylsiloxane/poly (methyl methacrylate) (PDMS/PMMA) blends were prepared by radical copolymerization of methyl methacrylate (MMA) and divinylbenzene (DVB) in the presence of PDMS. Elastomers based on PDMS/PMMA blends were formed by cross-linking PDMS with methyltriethoxysilane (MTES). Mechanical property measurements show that the elastomers thus formed exhibit superior tensile strength with respect to general room temperature vulcanized silicone elastomers containing silica. Moreover, investigations were carried out on the elastomers by extraction, scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) measurements. SEM shows that the elastomer has a microphase-separated structure consisting of dispersed PMMA domains within a continuous PDMS matrix. DSC result shows that the elastomers display two glass transition temperatures and confirm the incompatible nature of PDMS and PMMA.

Well-defined polyaniline nanotubes and nanofibers surface-modified with poly(methyl methacrylate) via in-situ radical polymerization

The well-defined polyaniline (PANI) nanotubes and nanofibers were prepared by the chemical oxidative polymerization of aniline with acrylic acid (AA) as both template and dopant. Then the acrylic acid doped PANI nanotubes and nanofibers (PANI-AA) were surface-modified with poly(methyl methacrylate) (PMMA) via the in-situ radical copolymerization of methyl methacrylate (MMA) and the AA molecules on the surfaces of the PANI-AA. The final one-dimensional nanostructured polyaniline exhibited excellent dispersibility in toluene. It indicated that PMMA had been successfully grafted from the surfaces of the one-dimensional nanostructured polyaniline. The molecular structure changes of the one-dimensional nanostructured polyaniline before and after the radical grafting polymerization were investigated with X-ray photoelectron spectroscopy (XPS).

Synthesis, Characterization and Thermolysis of Hyperbranched Homo- and Amphiphilic Co-Polymers Prepared Using an Inimer Bearing a Thermolyzable Acylal Group

Degradable hyperbranched polymers were synthesized via self-condensing atom transfer radical copolymerization of methyl methacrylate (MMA) with a novel inimer bearing a thermolyzable acylal group. This inimer was 1-(2-bromoisobutyryloxyl)ethyl methacrylate (BIB1EMA) and was synthesized in a one-step reaction between 2-bromoisobutyric acid and vinyl methacrylate at 40% yield. The inimer was subsequently used for the preparation of three degradable hyperbranched homopolymers of MMA (monomer conversion ∼80%) with molecular weights in the range from 36 000 to 51 000 g mol–1 synthesized using initial MMA-to-inimer molar ratios between 25 and 100. The inimer was also used for the preparation of two degradable hyperbranched amphiphilic copolymers of MMA and 2-(dimethylamino)ethyl methacrylate (DMAEMA) with an MMA hydrophobic hyperbranched core and different compositions, 10 and 38 mol % DMAEMA, afforded by changing the relative loadings in the two comonomers. Both hyperbranched amphiphilic copolymers were solubl...

Self‐complementary multiple hydrogen bonding interactions increase the glass transition temperatures to supramolecular poly(methyl methacrylate) copolymers

AbstractWe have prepared a series of poly(methyl methacrylate) (PMMA)‐based copolymers through free radical copolymerization of methyl methacrylate in the presence of 2‐ureido‐4[1H]‐pyrimidinone methyl methacrylate (UPyMA). The glass transition temperature was increased with the increase of UPyMA contents in PMMA copolymers due to strong self‐complementary multiple hydrogen bonding interactions of UPy moiety. The Fourier transform infrared and solid‐state NMR spectroscopic analyses provided positive evidence for the presence of multiple hydrogen bonds interaction of UPy moiety. Furthermore, the proton spin‐lattice relaxation time in the rotating frame [T1ρ(H)] for the PMMA copolymers had a single value that was less than pure PMMA, indicating the smaller domain sizes in PMMA copolymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Nitroxide-mediated radical copolymerization of methyl methacrylate controlled with a minimal amount of 9-(4-vinylbenzyl)-9H-carbazole

The controlled nitroxide-mediated homopolymerization of 9-(4-vinylbenzyl)-9H-carbazole (VBK) and the copolymerization of methyl methacrylate (MMA) with varying amounts of VBK were accomplished by using 10 mol % {tert-butyl[1-(diethoxyphosphoryl)-2,2-dimethylpropyl]amino} nitroxide relative to 2-({tert-butyl[1-(diethoxyphosphoryl)-2,2-dimethylpropyl]amino}oxy)-2-methylpropionic acid (BlocBuilder™) in dimethylformamide at temperatures from 80 to 125 °C. As little as 1 mol % of VBK in the feed was required to obtain a controlled copolymerization of an MMA/VBK mixture, resulting in a linear increase in molecular weight versus conversion with a narrow molecular weight distribution (Mw/Mn ≈ 1.3). Preferential incorporation of VBK into the copolymer was indicated by the MMA/VBK reactivity ratios determined: rVBK = 2.7 ± 1.5 and rMMA = 0.24 ± 0.14. The copolymers were found significantly “living” by performing subsequent chain extensions with a fresh batch of VBK and by 31P NMR spectroscopy analysis. VBK was found to be an effective controlling comonomer for NMP of MMA, and such low levels of VBK comonomer ensured transparency in the final copolymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Mesh-size control and functionalization of reorganizable chemical gels by monomer insertion into their cross-linking points

Mesh-size control of network structures of chemical gels, i.e. mesh expansion by insertion of styrene derivatives and mesh shrinking by insertion of divinylbenzene in the gels, was carried out. Chemical gels with alkoxyamine at their cross-linking points were synthesized by radical copolymerization of methyl methacrylate and divinyl monomer with alkoxyamine units. The monomers were inserted by heating the gels with each monomer separately, and the network size was evaluated by small-angle X-ray scattering (SAXS) measurements. Since a living polymerization procedure was adopted for the reactions, network mesh sizes were controlled precisely by controlling the reaction time and selecting an appropriate monomer. In addition, gel properties such as swelling degree and phase separation could also be controlled by employing functional monomers such as hydrophilic and fluorinated monomers. These reorganizable chemical gels combine the advantages of high stability of chemical gels with ease of structural changeability of physical gels.