PMMA@SCNC composite microspheres prepared from pickering emulsion template as curcumin delivery carriers

We demonstrate a facile route to prepare novel composite microspheres based on Pickering emulsion template stabilized by cellulose nanocrystals prepared from sisal fiber (SCNCs). The oil phase of the Pickering emulsions contains hydrophobic drug curcumin and poly(methyl methacrylate) (PMMA). Curcumin loaded PMMA composite microspheres coated by SCNCs (Cur‐loaded PMMA@SCNC CMs) were obtained after the evaporation of dichloromethane. The structure and morphology of CMs were characterized by polarized optical microscope (POM), confocal laser scanning microscope, scanning electric microscope, and Fourier transform infrared spectroscopy. The stability and release kinetics of curcumin were evaluated based on spectrophotometric measurements. Overall, these results show that Cur‐loaded PMMA@SCNC CMs display long‐term photostability and good encapsulating ability for curcumin. This work offers an effective route of preparing new functional microsphere for the delivery of bioactive compounds. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46127.     

Acetylsalicylic acid loading and release studies of the PMMA‐g‐polymeric oils/oily acids micro and nanospheres

Poly(methyl methacrylate) (PMMA) and PMMA copolymers derived from plant oils (Polylinseed oil‐g‐PMMA, Polysoybean oil‐g‐PMMA, Polylinoleic acid‐g‐PMMA (PLina‐g‐PMMA) and Polyhydroxy alkanoate‐ sy‐g‐Polylinoleic acid‐g‐PMMA (PHA‐g‐PLina‐g‐PMMA)) as hydrophobic polymers, a series of hydrophobic microsphere or nanosphere dispersions, were prepared by the emulsion/solvent evaporation method. The diameters of the nanospheres and microspheres were measured by dynamic light scattering with a zetasizer, optically and by scanning electron microscopy. The magnetic quality of the microspheres was determined by the electron spin resonance technique. Acetylsalicylic acid (aspirin, ASA) was used as a model drug and loaded into the microspheres during the preparation process. The effect of the stirring rate over the size and size distribution of the micro/nanospheres was evaluated, and the effects of copolymer types derived from plant oil/oily acids and the copolymer/drug ratios were evaluated. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

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     

Preparation and evaluation of composite microspheres of polyacrylamide‐grafted polysaccharides

The poor mechanical strength and instability of polysaccharide's gel takes away opportunities for versatile application. The grafting of polyacrylamide (PAM) onto polysaccharide was found to be an efficient tool for transforming its properties and obtaining stable and robust composite microspheres (CMs). In this study, free‐radical polymerization reaction was used for the grafting of PAM onto the polysaccharide backbone, and their hydrogel CMs were obtained through an ionotropic gelation method. Porous and buoyant CMs were obtained through the incorporation of sodium bicarbonate into the reaction mixture. Characterizations were done through Fourier transform infrared spectroscopy, thermal and scanning electron microscopy analysis. The mechanical strength and squeezing capacity were evaluated extensively through a modified syringe method developed in‐house. The squeezing capacity of grafted CMs diminished with the formation of a complex interpenetrating network. The Young's modulus, swelling kinetics, mechanical strength, and squeezing capacity of the grafted microspheres were compared extensively. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2912–2922, 2013     

Facile way to disperse single‐walled carbon nanotubes using a noncovalent method and their reinforcing effect in poly(methyl methacrylate) composites

In this work, a noncovalent method was used to functionalize and thereby disperse single‐walled carbon nanotubes (SWCNTs) in dimethylformamide with poly[methyl methacrylate‐co‐(fluorescein O‐acrylate)] as a surfactant, and then the resultant poly(methyl methacrylate) (PMMA)‐based nanocomposites were fabricated via solution casting. The dispersion level of carbon nanotubes in the solvent was investigated by means of scanning electron microscopy and atomic force microscopy. The results showed that carbon nanotubes were well wrapped by the surfactant, and small carbon nanotube bundles several nanometers or less in diameter and several micrometers in length were obtained. Both scanning electron microscopy and transmission electron microscopy confirmed the uniform dispersion of SWCNTs in the PMMA matrix. The mechanical properties of the composites were determined with a universal tension tester. The PMMA composite containing 2 wt % SWCNTs showed improved tensile properties versus neat PMMA, showing 56 and 30% enhancements of the tensile modulus and tensile stress, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation of heat resisting poly(methyl methacrylate)/graphite composite microspheres used as ultra‐lightweight proppants

Ultra‐lightweight heat resisting poly(methyl methacrylate) (PMMA)/graphite microspheres were successfully prepared via in situ suspension polymerization. The Fourier transform infrared and X‐ray powder diffraction results confirmed the successful preparation of the composite microspheres. Field emission scanning electron microscope analysis illustrated that the graphite particles were dispersed in microspheres and the PMMA/graphite composite microspheres had good sphericity and roundness. Furthermore, density analysis indicated that the apparent density of composites microspheres was about 1.055–1.135g/cm³ which was suitable for the transmission with water carrying. The results from thermodynamic test revealed that the thermal stability of the composite was significantly improved with increasing graphite content, which could be used as ultra‐lightweight proppant in deep underground. In addition, the crushing rate decreased to 0.5% with graphite ratio of 3.0% at the pressure of 69 MPa. Therefore, PMMA/Graphite composite microspheres exhibit a promising application in petroleum or gas exploitation as water carrying fracturing proppants. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41924.     

Solvent cast blends of PMMA microspheres in bisphenol-A-polycarbonate

Abstract

Transparent films of bisphenol-A-polycarbonate (PC), poly (methyl methacrylate) (PMMA) microspheres and their blends at various compositions were prepared by solution casting using methylene chloride (MC) as a solvent. The structural, morphological and thermal properties were investigated by Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry and thermogravimetric analysis. It was obvious that all the characteristic absorption bands could be found in the IR spectra of PC/PMMA blends, but different in the strength. From the SEM images, a co-continue morphology was observed in the PC/PMMA blends when the PMMA content was above 80wt%, indicating the existence of special interaction between PC and PMMA microspheres. Differential scanning calorimetry results showed a single glass transition temperature (T_g) only for 10%PC/90%PMMA blends because of the better dissolution of PC in PMMA than PMMA in PC. Thermogravimetric analysis thermograms showed that the thermal stability of PC/PMMA blends increased with increasing PC content, which was due to the better thermal stability of PC.     

Formation of porous glass via core/shell-structured poly(methyl methacrylate)/powder glass prepared by ultrasonic irradiation in liquid CO2

The formation of porous glass ceramic via core/shell-structured poly(methyl methacrylate)(PMMA)/powder glass was investigated. Core/shell structures were prepared via ultrasonic irradiation in high-pressure liquid carbon dioxide (CO₂) using PMMA microspheres as the core material and glass powder as the shell material. The mean particles sizes of PMMA template microspheres and glass powder were 9.8 μm and 0.9 μm, respectively. After removal of the PMMA template by calcination in air, porous glass was obtained. The products were characterized by scanning electronic microscopy (SEM) and thermogravimetric-differential thermal analysis (TG-DTA). The average pore diameter of porous glass was 4.3 μm. Compared with porous glass prepared by the other method, the porous glass prepared by ultrasonic irradiation of liquid CO₂ was achieved the narrow pore size distribution (CV = 35%) and the higher porosity (89%). The pores are not isolated and connected each other. Furthermore, the effects of experimental conditions, such as coating method, crosslink density of the template PMMA microspheres, ultrasonic intensity and calcination temperature, on the product morphology were investigated. The higher ultrasound intensity achieved the uniform coating of PMMA templates with powder glass. The calcination temperature and crosslinked density of PMMA template microspheres affect the pore structure.     

Double‐miniemulsion preparation of Fe3O4/poly(methyl methacrylate) magnetic latex

Magnetic poly(methyl methacrylate) (PMMA) microspheres were prepared by double‐miniemulsion polymerization. First, oleic acid coated magnetite particles synthesized by means of coprecipitation were dispersed into octane to obtain a ferrofluid. The ferrofluid and MMA were emulsified to form O/W emulsion, respectively. Subsequently two miniemulsions were mixed together for polymerization. The obtained magnetic polymer particles were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, X‐ray powder diffraction, and thermogravimetry. The results showed that oleic acid coated magnetite particles were well encapsulated in PMMA. The effects of initiator dosage and monomer concentration on the conversion of MMA were also investigated. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

PMMA/SiO2复合微球在常规乳液体系中的制备及其形态研究

以4-乙烯基吡啶(4-VP)为辅助单体,分别使用十二烷基硫酸钠(SDS)和OP-40(CA897)作乳化剂,在SiO2存在下用常规乳液聚合合成了PMMA/SiO2复合微球.在阴离子乳化剂体系中,通过改变聚合物乳胶粒大小可以得到不同形态的复合微球,在非离子乳化剂体系中,可以得到草莓型或核-壳形态的SiO2/PMMA复合微球,取决于单体滴加速度、乳化剂的浓度和单体/SiO2比.复合微球的形态通过透射电镜及扫描电镜进行表征.     

Preparation,characterization, and thermal properties of poly (methyl methacrylate)/boron nitride composites by bulk polymerization

Poly (methyl methacrylate)/boron nitride (PMMA/BN) composites were prepared by dispersing BN particles into methyl methacrylate monomer phase by bulk polymerization method. BN particles modified with silane coupling agent, γ‐methacryloxypropyl trimethoxy silane, were characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis. Effects of modified BN particle content on thermal conductivity were investigated, and the experimental values were compared with those of theoretical and empirical models. With 16 wt% of BN particles, the thermal conductivity of the composite was 0.53 W/(m·K), 1.8 times higher than that of pure PMMA. The microstructures of the PMMA/BN composites were examined by scanning electron microscopy, energy‐dispersive X‐ray analysis, and transmission electron microscopy. Dynamic mechanical analysis and thermogravimetric analysis traces also corroborated the confinement of the polymer in an inorganic layer by exhibiting an increase in glass‐transition temperatures and weight loss temperatures in the thermogram. Mechanical properties and electrical insulation property of the PMMA/BN composites were also determined. These results showed that PMMA/BN composites may offer new technology and business opportunities. POLYM. COMPOS., 36:1675–1684, 2015. © 2014 Society of Plastics Engineers     

TPP/PMMA复合物促进环氧树脂/酸酐体系的固化动力学研究

以三苯基膦(TPP)和甲基丙烯酸甲酯(MMA)为原料合成了TPP/PMMA复合物,用DSC研究了TPP/PMMA催化双酚A二缩水甘油醚(EP828)/甲基四氢苯酐(MTHPA)体系固化反应动力学。非等温固化动力学研究结果表明,转化率在20%～60%范围内,用Ozawa法能较好地描述环氧树脂/酸酐体系的固化反应过程。     

聚己内酯/纳米羟基磷灰石复合微球中的药物分布及体外释放

采用单乳化溶剂挥发法制备了聚己内酯[poly(ε-caprolactone),PCL]/纳米羟基磷灰石(nano-hydroxyapatite,n-HA)复合微球.使用两种具有不同水溶性的模型药物对硝摹苯胺(p-nitroaniline)和罗丹明B(RhodamineB,RhB),研究n-HA在复合微球中的作用.用扫描电子显微镜观察微球的表面形貌.通过紫外-可见光分光光度法计算药物载量和包封率.用共聚焦激光显微镜分析药物在微球中的分布.分别研究了PCL微球和PCL/HA复合微球的体外释放性质.复合微球可以持续释放药物4周以上,在前3 d的突释后,其释放曲线符合Higuchi扩散方程.n-HA的加入使较亲水药物RhB在复合微球中分布更均匀,对较疏水药物对硝基苯胺则影响不明显.n-HA减少了载亲水药物的复合微球在前 3d 的突释,并减缓了其后的释放速率.结果表明:PCL/n-HA复合结构的材料有希望作为一种新的长效药物释放载体应用.     

Optimization and characteristics of preparing chitosan microspheres using response surface methodology

In this study, response surface methodology (RSM) was employed to optimize preparation of chitosan microspheres (CMs). Firstly, Plackett–Burman design (PBD) was applied to screen out the factors, which influence preparation of CMs significantly. The results showed that the concentration of chitosan and acetic acid as well as the volume of toluene were the key factors. Then, steepest ascent experiment and Box–Behnken design were introduced to optimize the levels of the key factors. As a result, the appropriate conditions of preparing CMs were chosen as follows: 2% (w/v) chitosan, 1.7% (v/v) acetic acid, 7 mL span‐80, 488 mL toluene, 1100 rpm, 60 min (emulsification time), 10 mL formaldehyde, and 60 min (crosslinking time). Also, the morphology, size particle, and FTIR spectra of CMs were studied by scanning electron microscopy, small angle laser light scattering, and FTIR spectrometer. Results showed that CMs had quite smooth surface spherical and sharp size distribution, which indicated that the CMs were successfully prepared by W/O emulsification crosslinking method using RSM. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

PMMA／凹凸棒粘土复合材料的制备及其性能研究

以有机改性凹凸棒粘土为填料,采用原位聚合法制备了聚甲基丙烯酸甲酯（PMMA）／凹凸棒粘土（ATP）复合材料,通过红外光谱（FTIR）、扫描电镜（SEM）、热重（TG）、力学性能测试等方法对复合材料进行分析和表征。结果表明,改性凹凸棒粘土与PMMA的相容性良好,在PMMA中分散均匀。而其独特的一维纤维棒状结构也可以对PMMA在一定程度上起到补强、增韧作用,当凹凸棒粘土的加入量在1．5％时,其综合力学性能较佳。     

Studies on synthesis and characterization of poly(methyl methacrylate)‐bentonite clay composite by emulsion polymerization and simultaneous in situ clay incorporation

Well‐dispersed poly(methyl methacrylate) (PMMA)–bentonite clay composite was synthesized by emulsion polymerization using methyl methacrylate (MMA) monomer and 3% sodium carbonate treated bentonite clay. The composite lost its transparency normally encountered with the neat PMMA. The composite was characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), vicat softening point (VSP), dynamic mechanical thermal analysis (DMTA), and tensile studies. The morphology was investigated by scanning electron microscopy (SEM) and atomic forced microscopy (AFM) as well. The crystallography was studied to estimate the changes in crystallographic planes by X‐ray diffraction (XRD) analysis. The particle size distribution was compared amongst neat bentonite clay, neat PMMA and the composite. The FTIR spectra reveal the fact that no new primary valence bond is formed between the clay and PMMA. The thermal stability of the composite is significantly improved, as indicated by the TGA and VSP studies. A substantial increase in glass transition temperature (T_g) approximately, 10°C was recorded from the DMTA as both the storage modulus and tan δ values underwent inflexion at higher temperatures in case of the composite compared with the pristine PMMA. The XRD pattern indicates increase in basal “d” spacing for the composite. The morphology from both the SEM and AFM is quite supportive to well‐dispersed exfoliation. The incorporation of nanosized activated clay particles in PMMA during its in situ polymerization from MMA led to the formation of nanocomposites. POLYM. COMPOS., 2013. © 2012 Society of Plastics Engineers     

Effect of noncovalent chemical modification on the electrical conductivity and tensile properties of poly(methyl methacrylate)/carbon nanotube composites

Noncovalent chemical modification by initiated chemical vapor deposition technique is applied to carbon nanotubes (CNTs) to reduce average agglomerate size of the nanoparticles in the polymer matrix and to improve surface interaction between the composite constituents. CNT surfaces are coated conformally with thin poly(glycidyl methacrylate) (PGMA) polymer film and coated nanoparticles are incorporated in poly(methyl methacrylate) (PMMA) polymer matrix using solvent casting technique. Conformal PGMA coatings around individual nanotubes were identified by scanning electron microscopy analysis. Transmission electron microscopy and optical microscopy analyses show homogeneous composite morphology for composites prepared by using PGMA coated nanotubes. Fourier Transform Infrared and X‐ray photoelectron spectroscopy analyses show the successful deposition of polymer with high retention of epoxide functionality. PGMA coating of CNTs exhibits improvement in electrical conductivity and tensile properties of PGMA‐CNT/PMMA systems when compared with uncoated nanoparticles. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation of cadmium sulfide/poly(methyl methacrylate) composites by precipitation with compressed CO2

Cadmium sulfide (CdS) nanoparticles and poly(methyl methacrylate) (PMMA) were first synthesized in methyl methacrylate (MMA)/sodium bis(2‐ethylhexyl) sulfosuccinate (AOT) microemulsion, in which MMA acts as the solvent and monomer. Then compressed CO₂ was used as an antisolvent to precipitate the CdS and PMMA simultaneously. Using this method, a CdS/PMMA composite was successfully prepared. The CdS nanoparticles dispersed in the polymer matrices were characterized by transmission electron microscopy. The higher pressure is favorable to producing CdS nanoparticles of smaller size. The phase structure of the obtained composite was characterized by X‐ray diffraction, which reveals that cubic CdS particles were formed. The FTIR spectra of the composite showed that there is no chemical bonding or strong interaction between CdS and PMMA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1643–1648, 2004     

基于细乳化/溶剂蒸发法制备复合纳米色素

采用细乳化/溶剂蒸发（MESE）的方法,制备了溶剂型染料/聚甲基丙烯酸甲酯（PMMA）复合纳米色素。系统分析了不同实验参数,包括表面活性剂浓度、聚合物浓度、染料装载量及超声时间对所制备的染料/聚合物复合色素形态的影响。结合TEM、X射线光电子能谱（XPS）及元素分析,发现借助MESE法制备染料/PMMA复合色素纳米颗粒具备核壳异质的微观结构。借助紫外-可见分光光度计测试了溶剂型染料经包覆后在水油两相的迁移过程,其随着聚合物溶解所发生的动态变化证实了染料已封装于聚合物壳内。所制备的染料/聚合物复合纳米色素表现出优异的光学稳定性能、存储稳定性能及耐水牢度。     

Effects of SBA-15 and its content on MMA solution polymerization and PMMA composites

An ordered mesoporous material, such as SBA-15 was considered as a promising reinforcement agent for polymeric materials due to its large surface area and uniform pore structure. In this paper, poly(methyl methacrylate) (PMMA)/SBA-15 composites were prepared by in situ free-radical solution polymerization of MMA in the presence of SBA-15. The effects of SBA-15 content on solution polymerization and the properties of the final polymer composite were investigated. The PMMA molecular weight and its distribution in PMMA/SBA-15 composites were determined by gel permeation chromatography. Fourier-transform infrared spectra, X-ray diffraction, thermal gravimetric analysis (TGA), differential scanning calorimeter and dynamic mechanical analysis were used to characterize the structure and properties of the composites. The morphology of the composites was observed by scanning electric microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the monomer conversion dropped off, but the polymer average molecular weight increased upon the introduction of SBA-15 into solution polymerization process. When compared with pure PMMA, the storage modulus of the composites was improved and the highest improvement was acquired at 1 wt% of SBA-15, based on the monomer feed content. The glass transition temperatures of the composites were increased slightly. TGA results confirmed that the thermal stability of the composite was not influenced much and a higher degree of terminal vinyl groups was formed in the product of polymerization. SEM and TEM images indicated that SBA-15 particles were incorporated into the polymer matrix.