Synthesis,modification, and porous properties of new glycidyl methacrylate copolymers

Synthesis, copolymerization, and physicochemical properties of new, of different degrees of crosslinker tetrafunctional bis[4(2‐hydroxy‐3‐methacryloyloxypropoxy)phenyl]sulfide and glycidyl methacrylate copolymers are presented. The monomers were used for the synthesis of porous microspheres in the presence of pore‐forming diluents, decan‐1‐ol, and toluene. Influence of diluents composition on their porous structures was studied. Porous structure of the obtained microspheres in dry (from nitrogen adsorption–desorption measurements) states was studied. Their chemical structures were studied by the use of Fourier transform infrared. The number of epoxy groups of the obtained copolymers, their thermal properties (thermogravimetric analysis), and swelling characteristics in 10 solvents of different chemical nature were examined. Selected copolymers were modified by amines in the epoxide ring‐opening reaction. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

A comparative study on anti-UV non-spherical methacrylate polymer particles and anti-UV PVA nanofibers

Three types of anti-UV non-spherical polymer particles (AUNSPP) based on methacrylate and anti-UV PVA nanofiber were synthesized to study and compare their UV protection properties. In the first type of AUNSPP, polystyrene seeds were swollen with dichloromethane solution of 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl) phenol (TINUVIN^® 234, which hereafter is called TINUVIN), styrene, divinylbenzene, and 2,2′-azobisisobutyronitrile (AIBN). In the other two types of AUNSPP, poly(methyl methacrylate) seeds were swollen with dichloromethane solution of TINUVIN, methyl methacrylate, lauryl methacrylate, ethylene glycol dimethylacrylate, and AIBN. Subsequently, dichloromethane was evaporated from the swollen microspheres, and polymerization was accomplished by elevating the temperature of swollen particles to 70 °C. The final particles were assigned as P(S)/TINUVIN, P(S-DVB)/TINUVIN, P(LMA–EGDMA)/TINUVIN, and P(MMA–EGDMA)/TINUVIN composite microspheres. Anti-UV PVA nanofibers were prepared by dispersing P(S-DVB)/TINUVIN microparticles in PVA aqueous solution. Finally, this mixture was electrospun under ambient conditions. Particle size, size distribution, and morphology of the particles were investigated by SEM micrograph and image analyzer software (Image J). The presence of TINUVIN in P(S-DVB)/TINUVIN composite particles was confirmed by FTIR and phosphorescence spectroscopy. The UV protective properties of microcomposite particles and anti-UV nanofibers were studied by UV–Vis spectra of their polyurethane (PU) composite film. Comparatively, similar cutoff wavelength effects were observed in the range of 200–400 nm in all the samples. The obtained results showed consistent drop in the UV-blocking efficiency as the UV irradiation time increased. PU/PS/TINUVIN and PU/anti-UV nanofiber composite films showed the worst and best UV-blocking efficiency, respectively. After 200, 400, 600, 800, and 1000 h of UV irradiation time, the blocking efficiency of the PU–PS/TINUVIN composite films dropped from 80 to 72, 68, 65, and 59 %, and that of the PU/anti-UV nanofiber composite films dropped from 98 to 97, 94, 86, and 83 %.     

Preparation and Properties of Thermoplastic Expandable Microspheres With P(VDC-AN-MMA) Shell by Suspension Polymerization

Thermoplastic expandable microspheres (TEMs) having core/shell structure were prepared via suspension polymerization with vinylidene chloride (VDC), acrylonitrile (AN), and methyl methacrylate (MMA) as monomers and i-butane as blowing agent. TEMs were about 20 µm in diameter and had a hollow core containing i-butane. The influence of the monomer feed ratio and blowing agent content was researched. When the monomers composition of 58.4 wt% VDC, 28 wt% AN, 13.6 wt% MMA, and 32 wt% i-butane in oil phase, suspension polymerization could yield TEMs having good expansion properties. The maximum expansion volume was 25 times of original volume at about 111–120°C, the blowing agent content in microspheres was about 21.5 wt%. The T_m.e, T_o.e, and T_o.s. of the TEMs increased with the VDC content in the polymerizable monomers decreasing.     

Preparation of uniform poly(glycidyl methacrylate) porous microspheres by membrane emulsification–polymerization technology

Uniform poly(glycidyl methacrylate‐divinyl‐benzene) (P(GMA‐DVB)) and poly(glycidyl methacrylate‐ethylene dimethacrylate) (P(GMA‐EGDMA)) porous microspheres with several 10 μm were successfully prepared by membrane emulsification–polymerization technology. Conventional suspension polymerization method was first investigated by examining the effects of recipe components on the morphologies of P(GMA‐DVB), including stabilizer, diluent, and crosslinker to select a optimum recipe. The membrane emulsification–polymerization process was developed to prepare uniform PGMA porous microspheres as the following: the oil phase composed of monomer, diluent and initiator was pressed through membrane pores into the aqueous phase to form uniform droplets, and subsequent suspension polymerization was carried out. GMA and 4‐methyl‐2‐pentanol in the selected recipe were relatively hydrophilic, and therefore oil phase could wet the hydrophilic glass membrane and bring about polydispersed droplets. However, when isooctane was added as a component of diluents, the uniform droplets could be prepared by membrane emulsification method. In the membrane emulsification–polymerization, the coagulation between microspheres obviously decreased while yield of microspheres slightly increased. To extend the application of PGMA, as a trail, uniform P(GMA‐EGDMA) porous microspheres were also successfully prepared by membrane emulsification–polymerization with a isooctane contained diluent, even though EGDMA was more hydrophilic than DVB. Therefore, recipe was found the important factor to prepare uniform PGMA porous microspheres using membrane emulsification–polymerization method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5018–5027, 2006     

Synthesis of a new tetrafunctional monomer, 1,4‐di(2‐hydroxy‐3‐methacryloyloxypropoxy)phenol,and its copolymerization

The new aromatic tetrafunctional methacrylate monomer, 1,4‐di(2‐hydroxy‐3‐methacryloyloxypropoxy) phenol, and its application for the synthesis of porous microspheres have been presented. It was copolymerized with trimethylolpropane trimethacrylate in the presence of pore‐forming diluents mixture (chlorobenzene and 1‐decanol). The results indicate that composition of diluents mixture influence porous structure of copolymers. The porous structure of the copolymer obtained in the presence of 50% chlorobenzene was studied in detail. The results show that pore volume and the most probable pore size diameters determined for the copolymer in the dry and in the wetted states are different. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of uniform PMMA microspheres employing modified SPG (shirasu porous glass) emulsification technique

Application of the particulate microporous glass membrane (SPG) was extended to the synthesis of fairly monodisperse poly(methyl methacrylate) (PMMA) microspheres. Hydrophilic monomers have been believed to yield polymer particles of a broad size distribution when the SPG technique was employed. This difficulty was overcome by adopting the droplet swelling technique. The primary uniform emulsion composed of a mixture of hydrophobic diluent (and/or monomer), cosurfactant, and initiator was prepared with an SPG membrane and was allowed to absorb MMA (and diluent) under the principle of the degradative diffusion process from droplets in the secondary emulsion. The coefficient of variation of PMMA spheres was around 10%. Porous PMMA spheres possessing up to 185 m²/g of specific surface area were obtained as well as one-eyed spheres and smooth and solid spheres. © 1995 John Wiley & Sons, Inc.     

Synthesis,characterization, and in vitro release of ibuprofen from poly(MMA‐HEMA) copolymeric core–shell hydrogel microspheres for biomedical applications

This article describes the development of a new crosslinked poly(methyl methacrylate‐2‐hydroxyethyl methacrylate) copolymeric core–shell hydrogel microsphere incorporated with ibuprofen for potential applications in bone implants. Initially poly(methyl methacrylate) (PMMA) core microspheres were prepared by free‐radical initiation technique. On these core microspheres, 2‐hydroxyethyl methacrylate (HEMA) was polymerized by swelling PMMA microspheres with the HEMA monomer by using ascorbic acid and ammonium persulfate. Crosslinking monomers such as ethylene glycol dimethacrylate (EGDMA) has also been included along with HEMA for polymerization. By this technique, it was possible to obtain core–shell‐type microspheres. The core is a hard PMMA microsphere having a hydrophilic poly(HEMA) shell coat on it. These microspheres are highly hydrophilic as compared to PMMA microspheres. The size of the hydrogel microspheres almost doubled when swollen in benzyl alcohol. These microspheres were characterized by various techniques such as optical microscopy, scanning electron microscopy, Fourier‐transformed infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The particle size of both microspheres was analyzed by using Malvern Master Sizer/E particle size analyzer. The in vitro release of ibuprofen from both microspheres showed near zero‐order patterns. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3045–3054, 2002; DOI 10.1002/app.10310     

Synthesis and characterization of fluorinated poly(azomethine ether)s from new core-fluorinated azomethine-containing monomers

In this work, we describe the design and synthesis of novel core-fluorinated Schiff base monomers and conjugated polymers based on them. The new fully aromatic highly fluorinated poly(azomethine ether)s (PAMEs) were prepared by polycondensation of core-fluorinated azomethine-containing compounds. The structure of the monomers and polymers were confirmed by FTIR, ¹H, ¹³C, and ¹⁹F NMR spectroscopic analysis. The influence of synthesis condition on the properties of PAME compounds was investigated. Application of polarization microscopy with a temperature control thermal stage revealed thermotropic liquid crystalline (LC) behavior in the synthesized materials. Transition temperatures and a range of the existence of the LC phase were studied by a combination of the optical microscopy and DSC analysis. According to the TGA analysis, all the synthesized PAMEs show high thermal stability and thus offer a wide range of thermal processibility (up to 410–477 °C), which makes them prospective materials for many modern applications.     

Generation of meso- and microporous structures by pyrolysis of polysiloxane microspheres and by HF etching of SiOC microspheres

The porosity of polysiloxane microspheres obtained by emulsion processing of variably modified polyhydromethylsiloxane (PHMS) and subjected to pyrolysis in an Ar atmosphere at 450–650 °C was studied. Materials having micro- and mesopores with specific surface areas (SSAs) of up to 786 m²/g and pore volumes of up to 0.35 cm³/g were obtained. A high porosity was displayed by the microspheres heated at 600 °C that underwent deep depolymerization processes. Some polysiloxane microspheres were ceramized at temperatures of 1200–1500 °C and were subjected to etching by 35% aqueous HF. The microspheres heated to 1200–1400 °C were free of microcracks, whereas those ceramized at 1500 °C showed microcracks and macropores, although they preserved their spherical structure well. All of the microspheres ceramized at temperatures of 1200–1400 °C had low porosity. HF etching granted high micro- and mesoporosity to the materials ceramized at 1300–1500 °C. Microspheres heated at 1500 °C showed specific surface areas above 1000 m²/g after etching. These microspheres had low oxygen contents and were mostly composed of silicon carbide. Since they also showed macroporosity, HF etching of the polysiloxane microspheres ceramized at 1500 °C could be used to obtain hierarchically mesoporous-macroporous ceramic microspheres.     

Synthesis and characterization of methacrylate polymeric packings based on bisphenol‐S

The synthesis of new porous copolymers for chromatography purposes is presented. They are formed during the suspension and emulsion polymerization of methacrylate derivatives of bisphenol‐S with divinylbenzene in the presence of the pore‐forming diluent. One type of the obtained copolymers contains sulfonyl functional groups in its skeleton and the second sulfonyl and more polar hydroxyl groups. Chemical and porous structures of the obtained polymeric packings were studied. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 142–148, 2000     

Synthesis,structure, and properties of new methacrylic derivatives of naphthalene‐2,3‐diol

The synthesis of a new monomer, 2,3‐(2‐hydroxy‐3‐methacryloyloxypropoxy)naphthalene, and its copolymerization with divinylbenzene is presented. This monomer was obtained from naphthalene‐2,3‐diol in a two‐step synthesis. Copolymers in the form of porous microspheres were prepared by a suspension‐emulsion polymerization method. As pore‐forming diluents, toluene, 1‐decanol, benzyl alcohol, and their mixtures were used. In studies of their porous structure, two methods were used: the adsorption of nitrogen at low temperatures, which provided information about the porous structure of the material in a dry state, and inverse exclusion chromatography, which provided information about the porous structure of the polymer swollen by a good solvent. The obtained results suggest that the porous structures for the dry and swollen polymers were different. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1886–1895, 2006     

Design and UV-curable behaviour of boron based reactive diluent for epoxy acrylate oligomer used for flame retardant wood coating

Difunctional boron-containing reactive flame retardant for UV-curable epoxy acrylate oligomer was synthesized from phenyl boronic acid and glycidyl methacrylate. The synthesized reactive diluent was utilized to formulate ultraviolet (UV)-curable wood coatings. The weight fractions of reactive diluent in coatings formulation was varied from 5 to 25 wt % with constant photoinitiator concentration. The molecular structure of reactive flame retardant was confirmed by Fourier-transform infrared, Nuclear magnetic resonance (NMR) and ¹¹B NMR spectral analysis. Further, the efficacy of flame retardant behaviour of coatings was evaluated using limiting oxygen index and UL-94 vertical burning test. Thermal stability of cured coatings films were estimated from thermogravimetric and differential scanning calorimetry analysis. The effects of varying concentration of reactive diluent on the viscosity of coatings formulation along with optical, mechanical and chemical resistance properties of coatings were also evaluated. The coatings gel content, water absorption behaviour, contact angle analysis and stain resistance were also studied.     

SYNTHESIS,CHARACTERIZATION, AND THERMAL STABILITY OF HOMOPOLYMER AND COPOLYMER OF SOME 3-ARYL-2-HYDROXYPROPYL METHACRYLATES

Three new hydroxypropyl methacrylates having three different aryl rings were synthesized by addition of 2,3-epoxypropyl aromatic hydrocarbon to methacrylic acid. The monomers prepared are 3-phenyl-2-hydroxypropyl methacrylate, 3-tolyl-2-hydroxypropyl methacrylate, (THPMA), and 3-naphtyl-2-hydroxypropyl methacrylate. The homopolymers of these monomers and two different copolymers, [poly(THPMA-co-BMA)], were obtained from polymerization at 60°C in 1,4-dioxane solution using AIBN as initiator. All the monomers and the polymers were characterized by FT-IR and ¹H and ¹³C NMR techniques. Solubility parameters of the polymers and average molecular weight of poly(THPMA) were determined. Thermal stabilities of the polymers were given as comparing with each other by using TGA curves. Thermal degradation of poly(THPMA60%-co-BMA40%) was studied in detail.     

Optimization of structure and properties of polyphenylene sulfide porous membrane by controlling the process of thermally induced phase separation

Polyphenylene sulfide (PPS) porous membranes were successfully prepared from miscible blends of PPS and polyethersulfone (PES) via thermally induced phase separation followed by subsequent extraction of the PES diluent. The morphologies, crystalline structures, mechanical properties, pore structures and permeate fluxes of the PPS porous membranes obtained from different phase separation processes were characterized and are discussed. During the phase separation in the heating process, PPS and PES mainly underwent liquid–liquid phase separation, and then a nonhomogeneous porous structure with a mean pore size of 100 μm and a honeycomb‐like internal structure formed on the membrane surface. The phase separation of PPS/PES occurring in the cooling process was easier to control and the related pore diameter distribution was more regular. In the process of direct annealing, as the phase separation temperature decreased, the pore size distribution became more homogeneous and the mean diameter of the pores also decreased gradually. When the phase separation temperature decreased to 200 °C, PPS membranes with a network structure and a uniform as well as well‐interconnected porous structure could be obtained. In addition, the maximum permeation flux reached 1718.03 L m^–2 h^–1 when the phase separation temperature was 230 °C. The most probable pore diameter was 6.665 nm, and the permeate flux of this membrane was 2.00 L m^–2 h^–1; its tensile strength was 17.07 MPa. Finally, these PPS porous membranes with controllable pore structure as well as size can be widely used in the chemical industry and energy field for liquid purification. © 2020 Society of Chemical Industry     

Dependence of morphological changes of polymer particles on hydrophobic/hydrophilic additives

Fairly uniform microspheres of poly(styrene‐co‐methyl methacrylate) were prepared by employing a microporous glass membrane [Shirasu porous glass (SPG)]. The single‐step SPG emulsification, the emulsion composed mainly of monomers, hydrophobic additives, and an oil‐soluble initiator, suspended in the aqueous phase containing a stabilizer and inhibitor, was then transferred to a reactor, and subsequent suspension polymerization followed. The droplets obtained were polymerized at 75°C under a nitrogen atmosphere for 24 h. The uniform poly(styrene‐co‐methyl methacrylate) microspheres with diameters ranging from 7 to 14 μm and a narrow particle‐size distribution with a coefficient of variation close to 10% were prepared by using SPG membrane with a pore size of 1.42 μm. The effects of the crosslinking agent and hydrophobic additives on the particle size, particle‐size distribution, and morphologies were investigated. It was found that the particle size decreased with a narrower size distribution when the additives were changed from long‐chain alkanes to long‐chain alcohols and long‐chain esters, respectively. Various microspheres with different morphologies were obtained, depending on the composition of the oil phase. The spherical poly(styrene‐co‐methyl methacrylate) particles without phase separation were obtained when using an adequate amount of the crosslinking agent and methyl palmitate as an additive. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1013–1028, 2000     

Influence of starch granule swelling on graft copolymer composition. A comparison of monomers

Seven monomers, which varied widely in water solubility and ionic charge, were graft polymerized onto both unswollen starch and starch that had been swollen by heating in water to 60°C. Polymerizations were initiated with ferrous ammonium sulfate hexahydrate–hydrogen peroxide and, where applicable, with ceric ammonium nitrate. Graft copolymers were freed of ungrafted homopolymer by solvent extraction and were characterized by weight percentage of synthetic polymer incorporated in the graft copolymer, molecular weight of grafted branches, and grafting frequency. The influence of starch granule swelling on graft copolymer structure varied with the monomer used and could not be predicted on the basis of water solubility of monomer or its resulting polymer. With acrylonitrile and acrylamide, swollen starch gave higher molecular weight and less frequent grafts than unswollen starch. However, methyl methacrylate, N,N-dimethylaminoethyl methacrylate · HNO₃, N-t-butylaminoethyl methacrylate. HNO₃, and 2-hydroxy-3-methacryloyloxypropyltrimethylammonium chloride produced less frequent graft of higher molecular weight when starch was unswollen. With acrylic acid, graft molecular weight was independent of starch granule swelling, although grafting was less frequent when swollen starch was used.     

Porous structure and swelling properties of styrene–divinylbenzene copolymers for size exclusion chromatography

Small spherical particles of styrene–divinylbenzene copolymers have been synthesized by modified suspension polymerization. The effects of divinylbenzene (DVB) contents, dilution degree of the monomers and diluent composition on the porous structure and swelling properties of the copolymers were investigated. Toluene uptakes of macroporous copolymers were considered as a result of three contributions: filling of the fixed pores, expansion of the fixed or collapsed pores, and nuclei swelling and heptane uptakes as a result of the two first contributions. The increase of DVB content in the copolymers synthesized in presence of a solvating diluent (toluene) provoked a decrease on the nuclei swelling. The increase of dilution degree with solvating diluents changed the toluene and heptane uptakes, and when the diluent–copolymer affinity was reduced, the fixed pore volume increased. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1257–1262, 1997     

Polyethylenimine‐grafted and HSA‐immobilized poly(GMA–MMA) affinity adsorbents for bilirubin removal

The epoxy‐group‐containing microspheres from cross‐linked glycidyl methacrylate and methyl methacrylate, poly(GMA–MMA), were prepared by suspension polymerisation. The epoxy groups of the poly(GMA–MMA) microspheres were used for grafting with an anionic polymer polyethylenimine (PEI) to prepare non‐specific affinity adsorbents (poly(GMA–MMA)–PEI) for bilirubin removal. The specificity of the poly(GMA–MMA)–PEI adsorbent to bilirubin was further increased by immobilization of human serum albumin (HSA) via adsorption onto PEI‐grafted poly(GMA–MMA) adsorbent. Various amounts of HSA were immobilized on the poly(GMA–MMA)–PEI adsorbent by changing the medium pH and initial HSA concentration. The maximum HSA content was obtained at 68.3 mg g^?1 microspheres. The effects of pH, ionic strength, temperature and initial bilirubin concentration on the adsorption capacity of both adsorbents were investigated in a batch system. Separation of bilirubin from human serum was also investigated in a continuous‐flow system. The bilirubin adsorption on the poly(GMA–MMA)–PEI and poly(GMA–MMA)–PEI–HSA was not well described by the Langmuir model, but obeyed the Freundlich isotherm model. The poly(GMA–MMA)–PEI affinity microspheres are stable when subjected to sanitization with sodium hydroxide after repeated adsorption–desorption cycles. Copyright © 2004 Society of Chemical Industry     

Correlations for prediction of specific surface area and bulk and apparent densities of porous styrene‐divinylbenzene copolymers

Macroporous styrene‐divinylbenzene copolymers with different degree of crosslinking were prepared by suspension polymerization in presence of different binary mixtures of toluene and heptane, as diluent. Specific surface area, bulk and apparent densities, and pore volume of the resulting beads were determined experimentally. Applying the least square method to the experimental data, correlations for prediction of these properties were obtained. Effects of divinylbenzene concentration, diluent to comonomer volume ratio, and composition of the diluent mixture were considered in developing the aforementioned correlations. The influence of the reaction recipe on porous structure of the samples was also studied using scanning electron microscope (SEM). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of layered hierarchical porous SnO<Subscript>2</Subscript> for enhancing gas sensing performance

Layered hierarchical porous SnO₂ (LHP-SnO₂) have been synthesized by a two-step method, in which pure SnO₂ nanoparticles(NPs) with the diameter about 3.2 nm were prepared firstly through a hydro-thermal method, and then LHP-SnO₂ were prepared by utilizing polystyrene (PS) microspheres as a template and SnO₂ NPs as a precursor. The as-prepared sample consisted of porous SnO₂ layers, in which each layer presents a three-dimensional random arrangement of macropores with average pore diameter of about 260 nm. The Nitrogen adsorption–desorption analysis implied that the sample was characterized with large surface area of 140.67 m²/g and extensive micropores and mesopores structure. Compared with pure SnO₂ NPs, the LHP-SnO₂ exhibited an obvious improvement in gas sensing properties. These results indicate that the layered hierarchical porous structure possess potential application in sensing materials.