Narrow‐disperse or monodisperse crosslinked and functional core–shell polymer particles prepared by two‐stage precipitation polymerization

Narrow‐disperse and monodisperse cross‐linked core–shell polymer particles containing different functional groups, such as esters, hydroxyls, chloromethyls, carboxylic acids, amides, cyanos, and glycidyls, in the shell layers in the micrometer size range were prepared by a two‐stage precipitation polymerization in the absence of any stabilizer. Commercial divinylbenzene (DVB), containing 80% DVB, was precipitation polymerized in acetonitrile without any stabilizer as the first‐stage polymerization and was used as the core. Several functional monomers, including methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2‐hydroxyethyl methacrylate, glycidyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, t‐butyl acrylate, i‐octyl acrylate, acrylic acid, acrylamide, acrylonitrile, styrene, and p‐chloromethyl styrene, were incorporated into the shells during the second‐stage polymerization. The resulting core–shell polymer particles were characterized with scanning electron microscopy and Fourier transform infrared spectroscopy. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1776–1784, 2006     

Simultaneous interpenetrating polymer networks based on bromoacrylated castor oil polyurethane

In the first part of this study, simultaneous addition of bromine and acrylate to the double bonds of castor oil was achieved. In the second part of the study, bromoacrylated castor oil (BACO) was reacted with toluenediisocyanate (TDI), to form a prepolyurethane (BACOP). The prepolyurethanes were reacted with styrene (STY), 2‐hydroxyethyl methacrylate (HEMA), methyl methacrylate (MMA), and 3‐(acryloxy)‐2‐hydroxy propyl methacrylate (AHPMA) free radically, using the acrylate functional group to prepare the simultaneous interpenetrating polymer networks (SINs). 2,2′‐Azobis (isobutyronitrile) (AIBN) was used as the initiator and diethylene glycol dimethacrylate (DEGDMA) was used as the crosslinker. BACO and BACOP were characterized by IR, ¹H‐NMR, and ¹³C‐NMR techniques. Synthesized polymers were characterized by their resistance to chemical reagents, thermogravimetric analysis, and dynamic mechanical thermal analyzer (DMTA). All the polymers decomposed with 6–10% weight loss in a temperature range of 25–240°C. MMA‐type SIN showed the highest T_g (126°C), while STY‐type SINs showed the highest storage modulus (8.6 × 10⁹ Pa) at room temperature, with respect to other synthesized SINs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2947–2955, 2006     

Morphologies and dynamic mechanical properties of core‐shell emulsifier‐free latexes and their copolymers for P(BA/MMA)/P(MMA/BA) and P(BA/MMA)/PSt systems in the presence of AHPS

Different poly(methyl methacrylate/n‐butyl acrylate)/poly(n‐butyl acrylate/methyl methacrylate) [P(BA/MMA)/P(MMA/BA)] and poly(n‐butyl acrylate/methyl methacrylate)/polystyrene [P(BA/MMA)/PSt] core‐shell structured latexes were prepared by emulsifier‐free emulsion polymerization in the presence of hydrophilic monomer 3‐allyloxy‐2‐hydroxyl‐propanesulfonic salt (AHPS). The particle morphologies of the final latexes and dynamic mechanical properties of the copolymers from final latexes were investigated in detail. With the addition of AHPS, a latex of stable and high‐solid content (60 wt %) was prepared. The diameters of the latex particles are ～0.26 μm for the P(BA/MMA)/P(MMA/BA) system and 0.22–0.24 μm for the P(BA/MMA)/PSt system. All copolymers from the final latexes are two‐phase structure polymers, shown as two glass transition temperatures (T_gs) on dynamic mechanical analysis spectra. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3078–3084, 2002     

Thermal and sonochemical degradation kinetics of poly(n‐butyl methacrylate‐co‐alkyl acrylates): Variation of chain strength and stability with copolymer composition

The thermal degradation of poly(n‐butyl methacrylate‐co‐alkyl acrylate) was compared with ultrasonic degradation. For this purpose, different compositions of poly (n‐butyl methacrylate‐co‐methyl acrylate) (PBMAMA) and a particular composition of poly(n‐butyl methacrylate‐co‐ethyl acrylate) (PBMAEA) and poly(n‐butyl methacrylate‐co‐butyl acrylate) (PBMABA) were synthesized and characterized. The thermal degradation of polymers shows that the poly(alkyl acrylates) degrade in a single stage by random chain scission and poly(n‐butyl methacrylate) degrades in two stages. The number of stages of thermal degradation of copolymers was same as the majority component of the copolymer. The activation energy corresponding to random chain scission increased and then decreased with an increase of n‐butyl methacrylate fraction in copolymer. The effect of methyl acrylate content, alkyl acrylate substituent, and solvents on the ultrasonic degradation of these copolymers was investigated. A continuous distribution kinetics model was used to determine the degradation rate coefficients. The degradation rate coefficient of PBMAMA varied nonlinearly with n‐butyl methacrylate content. The degradation of poly (n‐butyl methacrylate‐co‐alkyl acrylate) followed the order: PBMAMA < PBMAEA < PBMABA. The variation in the degradation rate constant with composition of the copolymer was discussed in relation to the competing effects of the stretching of the polymer in solution and the electron displacement in the main chain. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Methyl methacrylate based copolymers and terpolymers: Preparation,identification, and plasticizing capability for a poly(methyl methacrylate) used in aviation

In this study, we first synthesized transparent poly(methyl methacrylate–maleic anhydride) [P(MMA–MAH)] and poly(methyl methacrylate–maleic anhydride–N‐2‐methyl‐4‐nitrophenyl maleimide) [P(MMA–MAH–MI)] via free‐radical polymerization at different monomer ratios. The synthesized polymers were characterized by titration, viscometric, spectroscopy, and thermal analyses. Higher contents of maleic anhydride (MAH) resulted in increases in the viscosity, glass‐transition temperature (T_g), and transparency. The synthesized polymers were then blended with a commercial‐grade poly(methyl methacrylate) (PMMA) used in aviation in the presence of CHCl₃. According to the free volume theory, the incorporation of 5 wt % P(MMA–MAH)s or P(MMA–MAH–MI)s into the commercial PMMA resulted in a plasticizing impact on this thermoplastic, which was confirmed by the decrease in the T_g values of the blends with almost the same transparency as the initial PMMA. In fact, the higher the content of MAH was, the lower the T_g of the blends was. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46603.     

Graft copolymerization of acrylate monomers onto sulfonated jute–cotton blended fabric

Graft copolymerization of acrylate monomers, e.g., methyl methacrylate and ethyl methacrylate, onto bleached sulfonated jute–cotton‐blended fabric was carried out in an aqueous medium, using potassium persulfate as an initiator under the catalytic influence of ferrous sulfate in a nitrogen atmosphere. The parameter variables, e.g., concentrations of monomer, potassium persulfate, ferrous sulfate, reaction time, and reaction temperature, directly influenced the percent graft yield. The percent graft yield increased to a certain value in each variable, and the percent graft yield of methyl methacrylate and ethyl methacrylate was about 15.9 and 17.1%, respectively. Polymer grafting was characterized by thermogravimetric analysis, infrared spectroscopy, and X‐ray diffractometry. Grafting improved the thermal stability, protected from photo‐oxidative degradation, decreased the dyeability, and had positive impact on fastness characteristics. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4393–4398, 2006     

Thermal behavior of graft copolymers of cotton cellulose and acrylate monomers

Cotton cellulose yarn was grafted with methyl acrylate, ethyl acrylate, n-butyl acrylate, and methyl methacrylate at various percentages of grafting. The effects of concentration of the initiator, concentration of the acid, and of temperature on grafting was studied and the mechanism discussed. The effect of reactivity of the monomer on the percentage graft-on is pointed out. Thermal behavior of natural and grafted cotton yarn was studied using dynamic thermogravimetry in air at a heating rate of 6°C/min up to a temperature of 500°C. The thermal stabilities of the samples grafted with various acrylate monomers to various percentages of grafting were computed from their primary thermograms by calculating the values of IDT, IPDT, and E^*. The results show that the thermal stability increases with increase in graft-on per cent, and the thermal stabilities of natural cotton and cotton grafted with different monomers are in the order ethyl > methyl > natural cellulose > methyl methacrylate > n-butyl acrylate.     

Photophysical studies of copolymers of N‐vinylcarbazole

The absorption, fluorescence excitation and emission spectroscopy, and time‐dependent spectrofluorimetry have been used to study the photophysics of copolymers of N‐vinylcarbazole with different monomers like vinyl acetate, methyl acrylate, methyl methacrylate, butyl acrylate, and butyl methacrylate in dichloromethane. In all the copolymers and at different N‐vinylcarbazole content, the absorption spectra reflect only the monomer carbazole units. The two kinds of excited monomer species of N‐vinylcarbazole are present in S₁ state. Short‐lived (～3 ns) excited monomer decays forming low energy excimer obtained by the complete overlap of the excited carbazole monomer. The long‐lived excited monomer (～8 ns) decays to ground state without formation of any excimer. The high energy excimer is relatively short‐lived and is formed by the partial overlap of the carbazole units. The presence of bulky group in the copolymer chain hinders the formation of excimers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 372–380, 2006     

Tris(trimethylsilyl)methyl functionalized 4‐chloromethyl styrene polymers: Effects of side chain modification on polymer structure and glass transition temperature

4‐Chloromethyl styrene was copolymerized with various molar ratio of methyl methacrylate or ethyl methacrylate by solution free radical polymerization method, at 70 ± 1°C using α,α′‐azobis(isobutyronitrile) as an initiator. Then, very highly sterically hindered tris(trimethylsilyl)methyl substituent was covalently linked to the obtained copolymers with liberation of chlorine atoms. The structure of all polymers was characterized and confirmed by FT‐IR, ¹H and ¹³C NMR spectroscopy techniques. The average molecular weight and glass transition temperature of polymers were determined using gel permeation chromatograph and differential scanning calorimeter instruments, respectively. Study of differential scanning calorimetry analyses showed that chemical modification of 4‐chloromethyl styrene copolymers with tris(trimethylsilyl)methyl substituents leads to an increase in the rigidity and glass transition temperature of polymers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 633–639, 2006     

Graft copolymerization of methyl acrylate onto poly(vinyl alcohol) initiated by potassium diperiodatonickelate(IV)

The graft copolymerization of methyl acrylate onto poly(vinyl alcohol) (PVA) with a potassium diperiodatonickelate(IV) [Ni(IV)]–PVA redox system as an initiator was investigated in an alkaline medium. The grafting parameters were determined as functions of the temperature and the concentrations of the monomer and initiator. The structures of the graft copolymers were confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. The Ni(IV)–PVA system was found to be an efficient redox initiator for this graft copolymerization. A single‐electron‐transfer mechanism was proposed for the formation of radicals and the initiation. Other acrylate monomers, such as methyl methacrylate, ethyl acrylate, n‐butyl acrylate, and n‐butyl methacrylate, were used as reductants for graft copolymerization. These reactions definitely occurred to some degree. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 529–534, 2003     

Pyrolysis of poly(methyl methacrylate co ethyl acrylate)

An investigation of the behavior of poly(methyl methacrylate co ethyl acrylate) with a commercially available filament-type pyrolysis unit and gas chromatogaph was conducted. It has been hypothesized that the quantity of ethyl acrylate monomer produced under the conditions of the experiment is dependent upon the number of ethyl acrylate–methyl methacrylate bonds contained in the copolymer. These observations were made possible by a standardized samples-handling technique in which a uniformsize disk was pyrolyzed at a maximum pyrolysis temperature of 600°C. This enabled reproducible pyrolysis gas chromatograms to be obtained and permitted pyrolysis products of copolymers containing different ratios of ethyl acrylate and methyl methacrylate to be compared. An examination of sequence distribution data, obtained with the aid of a sequence distribution program for copolymers, showed sufficient agreement with the pyrolysis data to support the hypothesis. It has been demonstrated that pyrolysis gas chromatography may be applied to experimentally determine the sequence distribution of copolymers.     

Photocrosslinkable copolymers based on 4‐acryloyloxyphenyl‐3′‐chlorostyryl ketone and methyl methacrylate: synthesis,comonomer reactivity ratios and UV photosensitivity

A new photosensitive acrylate monomer having a pendant chlorocinnamoyl moiety (APCSK) was copolymerized with methyl methacrylate (MMA) in different feed compositions in ethyl acetate solution at 70°C using benzoyl peroxide as a free‐radical initiator. The newly synthesized copolymers were characterized by FTIR, ¹H and ¹³C nuclear magnetic resonance (NMR) spectral techniques, as well as by size‐exclusion chromatography. Their thermal behaviour was assessed by thermogravimetric analysis in air and differential scanning calorimetry under nitrogen atmosphere. The copolymers exhibit no phase separation since there is only one glass transition temperature (T_g) value in the region of copolymer composition studied. The reactivity ratios of the comonomers were calculated by adopting linearization methods such as the Fineman–Ross (F‐R), Kelen–Tudos (K‐T) and extended Kelen–Tudos (ExtK‐T) methods, and by a non‐linear error‐in‐variables model method (EVM) using a computer program (RREVM). The results suggest that MMA is more reactive than APCSK and that their copolymerization leads to the formation of random copolymers. The photosensitivity of the copolymer samples was studied in solution as well as in thin films through UV irradiation. The influence of different factors, including solvent nature, concentration, temperature, photosensitizer and copolymer composition, on the rate of photocrosslinking of the photoreactive copolymers was investigated for effective industrial application of these polymers as negative photoresists. Copyright © 2004 Society of Chemical Industry     

Synthesis and characterization of oil sorbers based on docosanyl acrylate and methacrylates copolymers

Docosanyl acrylate (DCA) monomer was copolymerized with different monomer feed ratios of cinnamoyloxy ethyl methacrylate (CEMA) or methyl methacrylate (MMA) monomer to produce different compositions for DCA/CEMA or DCA/MMA copolymer with low conversions.¹H NMR spectroscopy was used to confirm the copolymer structure. DCA was crosslinked with different mol % of CEMA or MMA using dibenzoyl peroxide as initiator and various weight percentages of either 1,1,1‐trimethylolpropane triacrylates or 1,1,1‐trimethylolpropane trimethacrylates crosslinkers. The effects of monomer feed composition, crosslinker concentration, and the hydrophobicity of the copolymer units on swelling properties of the crosslinked polymers were studied through the oil absorbency tests. The network parameters, such as polymer solvent interaction (χ), effective crosslink density (υ_e), equilibrium modulus of elasticity (G_T), and average molecular weight between crosslinks (M_c), were determined and correlated with the structure of the synthesized copolymers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

n‐Butyl acrylate based latex interpenetrating polymer networks used as processing modifiers and impact modifiers of poly(vinyl chloride)

A latex interpenetrating polymer network (LIPN), consisting of poly(n‐butyl acrylate), poly(n‐butyl acrylate‐co‐ethylhexyl acrylate), and poly(methyl methacrylate‐co‐ethyl acrylate) and labeled PBEM, with 1,4‐butanediol diacrylate as a crosslinking agent was synthesized by three‐stage emulsion polymerization. The initial poly(n‐butyl acrylate) latex was agglomerated by a polymer latex containing an acrylic acid residue and then was encapsulated by poly(n‐butyl acrylate‐co‐ethylhexyl acrylate) and poly(methyl methacrylate‐co‐ethyl acrylate). A polyblend of poly(vinyl chloride) (PVC) and PBEM was prepared through the blending of PVC and PBEM. The morphology and properties of the polyblend were studied. The experimental results showed that the processability and impact resistance of PVC could be enhanced considerably by the blending of 6–10 phr PBEM. This three‐stage LIPN PBEM is a promising modifier for manufacturing rigid PVC. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1168–1173, 2004     

Synthesis of amphiphilic poly(methyl methacrylate)‐block‐poly(methacrylic acid) diblock copolymers by atom transfer radical polymerization

Atom transfer radical polymerization (ATRP) of 1‐(butoxy)ethyl methacrylate (BEMA) was carried out using CuBr/2,2′‐bipyridyl complex as catalyst and 2‐bromo‐2‐methyl‐propionic acid ester as initiator. The number average molecular weight of the obtained polymers increased with monomer conversion, and molecular weight distributions were unimodal throughout the reaction and shifted toward higher molecular weights. Using poly(methyl methacrylate) (PMMA) with a bromine atom at the chain end, which was prepared by ATRP, as the macro‐initiator, a diblock copolymer PMMA‐block‐poly [1‐(butoxy)ethyl methacrylate] (PMMA‐b‐PBEMA) has been synthesized by means of ATRP of BEMA. The amphiphilic diblock copolymer PMMA‐block‐poly(methacrylic acid) can be further obtained very easily by hydrolysis of PMMA‐b‐PBEMA under mild acidic conditions. The molecular weight and the structure of the above‐mentioned polymers were characterized with gel permeation chromatography, infrared spectroscopy and nuclear magnetic resonance. Copyright © 2005 Society of Chemical Industry     

Dynamic‐mechanical behavior of hydrophobic–hydrophilic interpenetrating copolymer networks

Sequential interpenetrating polymer networks (IPNs) were prepared by free‐radical polymerization. One of the components of the IPN was a poly(butyl acrylate) (PBA) network, and the other one was a poly(methyl methacrylate‐co‐hydroxyethyl methacrylate) copolymer network. Dynamic‐mechanical experiments show that the IPNs are phase separated: two main α relaxations occur in all samples, the low temperature one corresponding to the PBA network and that appearing at higher temperature due to the copolymer network. The latter shows a shape analogous to a pure poly(hydroxyethyl methacrylate) (PHEMA) network independently of the copolymer composition. The influence of water absorption on the dynamic‐mechanical spectrum shows that only a small amount of water reaches the butyl acrylate segments. The dependence of the mechanical behavior of the poly(methyl methacrylate‐co‐hydroxyethyl methacrylate) copolymer networks with the copolymer composition has been also analyzed. POLYM. ENG. SCI., 46:930–937, 2006. © 2006 Society of Plastics Engineers     

偏光片用压敏胶粘剂的合成及性能研究

采用聚合物共混改性的方法,以高、低分子量共聚物共混,使其分子量分布变宽,在保持较好的持粘力的情况下,改善初粘力和剥离强度。实验以丙烯酸丁酯、丙烯酸乙酯为软单体,甲基丙烯酸甲酯、甲基丙烯酸丁酯、甲基丙烯酸乙酯等为硬单体,以过氧化苯甲酰BPO为引发剂,甲苯和乙酸乙酯为溶剂,合成了一系列高、低分子量丙烯酸酯共聚物,再通过调节功能性单体丙烯酸AA的含量以及高、低分子量共聚物的共混配比,使压敏胶粘剂的性能得到了很好的改善。     

Investigation on preparation and property of nano‐CaCO3/PP masterbatch modified by reactive monomers

Nano‐CaCO₃/polypropylene (PP) masterbatch containing above 80 wt % nano‐CaCO₃ was prepared by nano‐CaCO₃ coated PP modified by reactive monomers. The chemical interaction, crystallization and melting behavior, thermal stability, morphology, and surface contact angle of masterbatch were investigated with IR, DSC, TEM, TGA, ESCA, and surface contact angle. The results indicated that nano‐CaCO₃ was coated by PP graft copolymers in the masterbatch modified by reactive monomers. The graft ratio and crystallization and melting behavior of PP in the masterbatch depended on the type and content of reactive monomer. The crystallization temperatures of masterbatch modified by reactive monomer is methyl methacrylate > butyl acrylate > methyl acrylate ≈ mixture of acrylic acid and styrene > unmodified ≈ maleic anhydride ≈ acrylic acid > styrene. Modification by reactive monomer increased the thermal stability and surface contact angle of masterbatch. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3907–3914, 2006     

A novel type of Si‐containing acrylic resins: Synthesis,characterization, and film properties

A novel type of Si‐containing acrylic resins was prepared by two steps and investigated their usage as surface coatings materials. At first a reactive polysiloxane intermediate Z‐6018 was reacted with 2‐hydroxyethyl methacrylate (HEMA) in toluene at 110°C under N₂ atmosphere. After the condensation reaction was stopped, reacted with different acrylic ester monomers such as ethyl acrylate (EA) and methyl methacrylate (MMA) at different mole ratio (1/3 and 1/4) by the free radical addition polymerization. Structures of Si‐containing acrylic resins were characterized by Fourier Transform Infrared Spectrometer (FTIR) and thermal properties of these resins were investigated by thermogravimetric analysis and differential scanning calorimetry DSC techniques. Surface coating properties of the films prepared from these resin were also determined. The results showed that all films are flexible, glossy or semi gloss and have excellent drying and adhesion properties. All films also exhibit abrasion resistances moderately. Water resistance of the films was generally modified by cured in oven and alkaline resistance of the films prepared from resins containing ethyl acrylate units are excellent. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Influence of the chemical structure of dithiocarbamates with different R groups on the reversible addition‐fragmentation chain transfer polymerization

Four dithiocarbamates, carbazole‐9‐carbodithioic acid benzyl ester (R1), carbazole‐9‐carbodithioic acid naphthalen‐1‐ylmethyl ester (R2), 2‐(carbazole‐9‐carbothioylsulfanyl)‐2‐methyl‐propionic acid ethyl ester (R3), and (carbazole‐9‐carbothioylsulfanyl)‐phenyl‐acetic acid methyl ester (R4), were synthesized and used to the reversible addition‐fragmentation chain transfer (RAFT) polymerizations of styrene (St), methyl methacrylate (MMA), and methyl acrylate (MA), respectively. The influence of chemical structure of dithiocarbamates with different R groups on the RAFT polymerizations was investigated. The results showed that the four RAFT agents were effective RAFT agents for the polymerizations of styrene or MA, and that the polymerizations were well‐controlled with the characteristics of controlled/“living” polymerization. The polymerization rate of styrene with thermal initiation was markedly influenced by the chemical structures of the group R in dithiocarbamates, and decreased in the order of R3 > R2 > R4 > R1. For the polymerization of MA, the efficiency of RAFT agents was in the following order: R2–R3 > R1 > R4. However, they were not efficient enough to control the polymerization of MMA. The obtained polystyrene (PSt) with carbazole group labeled strongly absorbed UV light at 294 nm and emitted fluorescent light in N,N‐dimethyl formamide (DMF). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 982–988, 2007