Synthesis and characterization of a soybean oil‐based macromonomer

An acrylate‐functional soybean oil‐based macromonomer (SoyAA‐1) was synthesized in high yields utilizing sequential amidation and acrylation processes to serve as an internal plasticizer in emulsion polymers. The structure and structure–property relationships of this unique macromonomer were validated with FTIR, NMR, and LC‐MS. The viability of SoyAA‐1 as a comonomer in emulsion polymerization was established via copolymerization with methyl methacrylate (MMA) at varying copolymer weight compositions. The effect of increasing SoyAA‐1 levels and concomitantly higher allylic functionality was measured through film coalescence, minimum film forming temperature, and initial and progressively increasing glass transition temperature(s). The results indicate that synthetic modification of a renewable resource, soybean oil, can yield a valuable monomer that can be copolymerized in high yields via emulsion polymerization to produce practical and mechanically stable latexes for a variety of coatings applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40249.     

Preparation and characterization of graphene‐agar and graphene oxide‐agar composites

Biodegradable counterparts of petro plastics for packaging applications are highly desired due to environmental considerations. Agar can be a potential material due to its availability and biodegradability. However, moderate mechanical strength and thermal stability, in addition to poor resistance against water, needs to be addressed before agar can be commercially implemented as packaging material. As a step toward this objective, graphene oxide (GO) and reduced GO (RGO) were incorporated in agar and were solution casted in the form of films. The tensile strength was increased by 118.4% and 69.4% at 2% GO and 2% RGO loading, respectively. Higher interfacial bonding between GO and agar compared to that of RGO and agar was attributed for the observed mechanical properties. Resistance to swelling and hydrophobicity (contact angle) of the composite were improved as well when compared to pure agar. The tensile strength and the contact angle values were however, decreased after the addition of 2% GO and 2% RGO. The morphological investigation showed that the formation of pores at higher concentration of reinforcement was the contributing factor for the decrease in tensile strength. No significant change in thermal properties was observed. The transmittance value was reduced to 0% after the incorporation of GO and RGO. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45085.     

Preliminary evaluation of packaging‐content interactions: Mechanical and physicochemical characterization of polylactide bottles

Biodegradable materials as polylactide (PLA) are very interesting for cosmetic packaging application. However, these polymers, under environmental conditions or/and chemical treatments, can undergo “aging,” compromising their performances such as container. The aim of this study was the evaluation of mechanical, physicochemical, and organoleptic properties of PLA bottles present in the cosmetic market. In particular, mechanical tests and thermal analyses were applied to study the PLA container degradation under stressed physicochemical conditions. Calorimetric and morphological analyses were applied to evaluate differences between internal and external surface of containers. Results highlighted that the heating process together with chemical treatment determined a significant modification on polymer, leading to a more resistant and fragile material, whereas the only physical or chemical treatment alone showed a plasticizing effect. In conclusion, this study represents a start point to evaluate content–packaging interactions to optimize the choice of PLA polymer as cosmetic packaging. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40067.     

Synthesis,characterization and application of novel polyacrylamide‐grafted barley

Polyacrylamide‐grafted barley (BAR‐g‐PAM) was synthesized by ceric ion‐based conventional method. The grafting of polyacrylamide chains on the polysaccharide backbone was confirmed through various physicochemical techniques such as intrinsic viscosity measurement, ¹³C‐NMR spectra, FTIR spectroscopy, elemental analysis, scanning electron microscopy morphology, thermogravimetric analysis study, number‐average molecular weight, and aqueous solubility. Furthermore, flocculation efficacy of the graft copolymers was studied in coal fine suspension through “jar test” procedure, toward its possible application as a novel flocculant for treatment of coal washery effluent. BAR‐g‐PAM is reported as a novel flocculant that can be used for bulk treatment of coal washery effluents. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41046.     

Preparation,characterization, and release behavior of ceftiofur‐loaded gelatin‐based microspheres

Drug‐loaded microspheres prepared from biomacromolecules have received considerable interest. In this article, we report a facile method for preparing ceftiofur‐loaded gelatin‐based microspheres for controlled release. We investigated the effects of factors, including the rotational speed, concentration of surfactant, concentration of gelatin, and ratio of water to oil (W/O), on the morphologies of gelatin microspheres and obtained the optimized conditions; for a typical average diameter of about 15 μm, these were 1000 rpm, a concentration of span 80 of 2.0%, a gelatin concentration of 20%, and a W/O of 1:20. Gelatin microspheres loaded with ceftiofur, ceftiofur‐Na, and ceftiofur‐HCl were prepared and characterized by scanning electron microscopy and laser light scattering. In vitro release studies were carefully performed for microspheres prepared with different crosslinker contents, loaded with different drugs, and blended with chitosan. The loaded ceftiofur showed an obviously longer release time compared with pure ceftiofur powder. A higher content of crosslinker led to a longer release time, but when the content reached 5%, the microspheres had a significantly cracked surface. The results also indicate that the blending of a small amount of chitosan could greatly prolong the release time. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2369–2376, 2013     

Hydroxypropylmethyl cellulose‐based sponges loaded self‐microemulsifying curcumin: Preparation,characterization, and in vivo oral absorption studies

Novel hydroxypropylmethyl cellulose (HPMC)‐based sponges containing self‐microemulsifying curcumin (SME‐Cur) were prepared by a freeze drying method using different grades of HPMC (E5 LV, E15 LV, E50 LV, A15 LV, and A4C). The physical properties and drug release from these carriers were characterized and compared among the different formulations. The mean pore size values of the sponges from image analysis ranged from 43.36 ± 4.54 to 123.22 ± 8.19 nm. An increase in the concentration or viscosity of the HPMC, resulted in denser sponges and a slower drug release. The average microemulsion droplet size from the optimal sponge formulation was 34.80 ± 0.1 nm, and the curcumin was almost completely released within 120 min. The AUC after oral administration of the liquid and solid SME‐Cur were 7‐ and 5‐fold greater than that of the curcumin powder in the rabbit, respectively. The results demonstrated that the HPMC‐based sponges loaded with SME‐Cur could be efficiently used to enhance the oral bioavailability and might be useful as they could be administered at a lower dose compared to normal curcumin powder. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42966.     

Development and characterization of a poly (vinyl alcohol) and sodium alginate blend foam for wound dressing loaded with propolis and all-trans retinoic acid

Propolis is a complex mixture of phytochemicals, with antibacterial, anti-inflammatory, and healing properties. All-trans retinoic acid is implicated in wound healing by stimulating angiogenesis, cell recruitment, extracellular matrix deposition, and reepithelization. The incorporation of both agents to a polymeric wound dressing composed of poly (vinyl alcohol) and sodium alginate may result in improved healing allied to controlled release, fluid uptake, and wound protection. In the present work, we have physically characterized this wound dressing and analyzed its release kinetics. The anti-inflammatory capacity was assayed. SEM images showed a highly porous structure with a diverse morphology. FTIR spectra displayed a highly cross-linked structure with both polymers connected by hydrogen bonds and acetal bridges. The wound dressings were able to retain great volumes of PBS. Propolis and vitamin A releasing behavior were maintained for 6 h. The concentrations of the biologically active substances were capable of promoting anti-inflammatory action in an erythrocyte membrane stabilization model. The wound dressings obtained here showed adequate physical properties. The fabrication process did not affect the anti-inflammatory capacity. Further tests are needed to ensure the biocompatibility and to assess other biological activities of the therapeutic agents.     

In vitro comparative biodegradation analysis of salt‐leached porous polymer scaffolds

This study presents a comprehensive, side‐by‐side analysis of chemical, thermal, mechanical, and morphological changes in four polymers used in tissue engineering: poly(glycerol‐sebacate) (PGS), poly(lactic acid) (PLA)/poly(ε‐caprolactone) (PCL) blend, poly(lactic‐co‐glycolic acid) (PLGA), and Texin 950, a segmented polyurethane resin (PUR). Polymer foams were created using a salt‐leaching technique and then analyzed over a 16‐week period. Biodegradation was analyzed by examining the morphology, thermal properties, molecular weight, chemical, and mechanical properties using scanning electron microscopy, differential scanning calorimetry, gel permeation chromatography, attenuated total reflectance‐Fourier transform infrared spectroscopy, thermogravimetric analysis, and compression testing. PGS underwent the most rapid degradation and was hallmarked by a decrease in compressive modulus. PLA/PCL blend and PLGA both had rapid initial decreases in compressive modulus, coupled with large decreases in molecular weight. Surface cracks were observed in the PUR samples, accompanied by a slight decrease in compressive modulus. However, as expected, the molecular weight did not decrease. These results confirm that PUR does not undergo significant degradation but may not be suitable for long‐term implants. The biodegradation rates of porous PGS, PLA/PCL blend, and PLGA found in this study can guide their use in tissue engineering and other biomedical applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Self‐driven graft polymerization of vinyl monomers on poultry chicken feathers in the absence of initiator/catalyst

An efficient and simple method for graft copolymerization of powdered chicken feather (CF) with vinyl monomers without any free radical initiator is reported. Various vinyl monomers such as glycidyl methacrylate (GMA), styrene (S), and methyl methacrylate (MMA); (20–60 wt % with respect to CF) were successfully grafted to chicken feather (CF) by using sodium dodecyl sulfate (SDS, 0.086–0.5 mmol) in the absence of any catalyst or initiator. Most likely, the hydrophilicity, hydrophobicity, and complex forming properties of chicken feather keratin with surfactant molecules were responsible for efficient grafting of polymers on CF surface. The effect of polymerization conditions, such as monomer concentration, temperature, and time of reaction, on the grafting parameters such as monomer conversion, grafting efficiency, and molar grafting ratio were studied. The described method showed a good potential of using low cost, easily accessible poultry chicken feathers as grafting material and self catalyzing agent for graft copolymerization with vinyl monomers to produce low cost commodity plastic for various end uses. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44645.     

Field performance on lettuce crops of poly(butylene adipate-co-terephthalate)/polylactic acid as alternative biodegradable composites mulching films

This work developed biodegradable poly(butylene adipate-co-terephthalate)/polylactic acid (PBAT/PLA) composites with different fillers to improve their physicochemical properties and biodegradability. The films were tested considering mechanical, morphological, thermal, crystalline, biodegradability, and ecotoxicity tests. Mechanical and morphological results indicated that the fillers' nature influences mechanical performance; all composites showed high-tensile strength (~30 MPa) than the pristine films (~12 MPa). The use of both fillers resulted in an interface, improving the matrix compatibility, reflecting in good thermal performance, low-water absorption, and high hydrophobicity. The WA (water absorption) and hydrophobicity are essential to maintain the crop's moisture since the water lost through plant transpiration will be condensed and returned to the soil. Films showed biodegradability and absence of toxicity, which allows the substitution of polyethylene commodity films as mulching films. Biodegradation and ecotoxicity tests indicate that the developed films are beneficial for lettuce crops and contribute to the development of seedlings.     

Synthesis and characterization of star‐shaped PLLA with sorbitol as core and its microspheres application in controlled drug release

The purpose of this study was to investigate the suitability of a six‐arm star‐shaped poly(l ‐lactide)s (s‐PLLA) as controlled drug carriers for hydrophobic drug molecules. First, s‐PLLA was synthesized by ring‐opening polymerization of l ‐lactide using sorbitol as initiator and stannous octoate as catalyst. The structure and molecular weight (M_w) of s‐PLLA was characterized with ¹H NMR, ¹³C NMR, and GPC. Second, rifampicin (RIF) used as a model drug was encapsulated within the microspheres of s‐PLLA via oil‐in‐water emulsion/solvent evaporation technique. The morphology, drug encapsulation efficiency (EE), and in vitro release behavior of the prepared microspheres were studied in details. Results indicated that the average diameters of s‐PLLA microspheres can be controlled between 8 and 20 µm by varying the copolymer's concentration or M_w . The EE of RIF was mainly determined by the concentration of s‐PLLA. The in vitro study showed that the burst release behavior can be depressed by increasing the M_w of the s‐PLLA. Present work suggests that the synthesized s‐PLLA could be used as a new material for drug delivery. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42213.     

Polyurethane‐functionalized starch nanoparticles for the purification of biodiesel

Polyurethane‐functionalized starch nanoparticles (PUFSNPs) have been synthesized by chemical modification of polyhydroxylated starch nanocrystals (SNC) with aliphatic and aromatic diisocyanates. The covalent attachment of the diisocyanates to the backbone of SNC for the formation of starch‐derived nanopolyurethane polymers was unambiguously determined by FTIR and NMR spectroscopy. PUFSNPs were entirely obtained from SNC with yields ranging from 41.5 to 86.0 wt % and their size distribution, size, porosity and morphology were determined by dynamic light scattering (DLS), high resolution transmission electron microscopy (HRTEM) and Brunauer–Emmett–Teller (BET) adsorption techniques. The size and surface area of the cyclic aliphatic‐based PUFSNP (NPU4) is 27 nm and 52.64 m² g^?1, respectively, indicating one of the potential and promising biodegradable materials for the adsorption of acid impurities and contaminants that are found in crude biodiesel. The acid content of the biodiesel is remarkably reduced by 32–39% with PUFSNPs while 7–18% with their corresponding bulk materials. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44463.     

Synthesis and characterization of high‐molecular weight aliphatic polyesters from monomers derived from renewable resources

A series of high‐molecular weight aliphatic polyesters have been synthesized, at temperatures of < 200°C, through a polycondensation reaction between 1,4‐butanediol and three diacids of different chain length (succinic acid, azelaic acid, and sebacic acid). All the polyesters obtained have a bio‐based content of 100% and number average molecular weight in the range of 28,000–116,000 Da. These average molecular weights are about 5–10 times higher than those of most reported aliphatic polyesters synthesized through similar reaction routes but at temperatures > 230°C. The over‐heating phenomenon, i.e., the observation of thermal degradation behavior of these polyesters at 230°C is reported. The crystallization behavior, mechanical properties, and enzymatic hydrolysis rate of the polyesters obtained are characterized. Poly(butylene succinate) (PBSu) shows the highest crystallinity and melting temperature, but the lowest thermal stability and slowest potential rate of enzymatic biodegradation rate compared with poly(butylene azelate) and poly(butylene sebacate). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40579.     

Theophylline‐loaded pectin‐based hydrogels. I. Effect of medium pH and preparation conditions on drug release profile

In this study, a series of theophylline‐loaded calcium pectin gel films were prepared in three different Ca⁺² concentrations with three different methods for wound dressing applications. Drug release performance of the films were investigated in four different medium pH in order to mimic wound healing pH conditions. Hydrogel films were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy and atomic force microscopy. Their absorbency (fluid handling), swelling behavior, dehydration rate, dispersion characteristic, dressing pH determination, water vapor permeability, oxygen permeability, surface contact angle, flexibility, Shore A hardness, mean mass per unit area and thickness were determined. The effect of the hydrogels on wound healing was evaluated with an in vitro wound healing assay. After evaluating all data, we suggested that the hydrogel film prepared with swelling method using 7% or 10% crosslinker and dried at 26 °C is more suitable for controlled drug release process. We showed that between pH 3.25 and 7.12 the form of the hydrogel did not change, and drug release was continuous. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46731.     

Ultra‐microstructural features of perborate oxidized starch

Ultrafine structures of low, medium, and highly oxidized starches, symbolized as LOS, MOS, and HOS, respectively, were thoroughly investigated. These oxidized starches were obtained by treatment of native starch (NS) with three different concentrations of sodium perborate (SPB). Thus, obtained products were studied with respect to major chemical and fine physical characteristics vis‐a‐vis these of NS (a) acidic and reduced groups creation along with mode of association, (b) significant increase in solubility, and (c) outstanding decrease in apparent viscosity. Thermogravimetric analysis (TGA) revealed thermal stability of the said substrates follows order: HOS > MOS > LOS > NS. Scanning electron micrographs (SEM) showed polygonal or irregular shape with particle size ranging from 2 to 20 μ. After oxidation, the starch surface became rough and the edges lost their definiteness completely. In conclusion, SPB is an efficient oxidant to produce oxidized starches with useful characteristics, which advocate them to wide applications in textile sizing and medicinal domains. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40170.     

Production and characterization of films containing poly(hydroxybutyrate) (PHB) blended with esterified alginate (ALG‐e) and poly(ethylene glycol) (PEG)

Alternative materials have long been studied and developed to replace conventional skin dressings with the emergence of new biopolymers and development of polymeric film fabrication techniques. As a new material for polymeric dressings, films of poly(hydroxybutyrate) (PHB) blended with esterified alginate (ALG‐e) and poly(ethyleneglycol) was studied. The esterification of sodium alginate (ALG‐e) generated a material with some amphiphilic characteristics and increased compatibility with the PHB. PEG was added as plasticizer in PHB/ALG‐e films was also tested, since PEG is often used in blends with PHB to improve flexibility and reduce hydrophobicity. At the amounts studied, it was found that both PEG and ALG‐e increase the degree of crystallinity, but a decrease was observed in the hydrophobic nature of PHB films. At the maximum concentration of ALG‐e and PEG used an increase in water vapor permeability and a decrease in tensile strength was reached due to the synergistic effect caused by better homogenization of PEG and ALG‐e in the PHB matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44362.     

Biobased thermosetting resins composed of L‐lysine methyl ester and bismaleimide

Lysine methyl ester (LME), which was generated in situ by the reaction of lysine methyl ester dihydrochloride and triethylamine in dimethyl sulfoxide (DMSO), was prepolymerized with 4,4′‐bismaleimidodiphenylmethane (BMI) at 80°C for 2 h in DMSO. Then, the formed prepolymer was precipitated in water. The obtained LME/BMI prepolymers with molar ratios of 2:2, 2:3, and 2:4 were compression‐molded at a final temperature of 230°C for 2 h to produce cured lysine methyl ester/4,4′‐bismaleimidodiphenylmethane resins (cLBs; cLB22, cLB23, and cLB24, respectively). Fourier transform infrared (FTIR) analyses revealed that the Michael addition reaction of amino groups to the C?C bonds of the maleimide group occurred in addition to the homopolymerization of the maleimide group. The glass‐transition temperature (T_g) and 5% weight loss temperature (T₅) of the cured resin increased with increasing BMI feed content, and cLB24 showed the highest T_g (343°C) and T₅ (389°C). The flexural strengths (131–150 MPa) and moduli (3.0–3.6 GPa) of the cLBs were comparable to those of the conventionally cured resins of BMI and 4,4′‐diaminodiphenylmethane. Field emission scanning electron microscopy analysis revealed that there was no phase separation for all of the cured resins. Although cLB23 and cLB24 were not biodegradable, cLB22 had a biodegradability of 8.5% after 30 days in an aerobic aqueous medium containing activated sludge. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40379.     

Recyclable bio‐based crosslinked polyurethanes with self‐healing ability

We report the synthesis of a linear bio‐based polyurethane (bio‐PU) containing furan ring by using renewable polylactide copolymer diol and 2,5‐furandimethanol as a soft segment and chain extender, respectively, in which the reversible crosslinked covalent bonds between hard segments were incorporated via Diels–Alder (D‐A) reaction between the furan ring of the chain extender and bismaleimide (BM) crosslinker. By simply controlling the amount of BM, mechanical properties of the obtained crosslinked bio‐PUs (CBPUs) were varied widely. In particular, the CBPU100 sample shows the highest tensile strength of 10.8 MPa, Young's modulus of 193 MPa, and an elongation of 155%. The differential scanning calorimetry experiments verify the recycle property of the CBPUs by the D‐A/retro‐D‐A reaction at the proper temperature. The thermal recyclability and remolding ability of these materials are demonstrated by two kinds of polymer processing methods, i.e., solution casting and hot‐compression molding. The recycled CBPUs display almost identical elongation and slightly decreased tensile strength compared to the as‐synthesized samples. Furthermore, the CBPUs also exhibit excellent self‐healing ability. Therefore, the resulting CBPUs possess tunable mechanical properties, good thermal recyclability, re‐mending, and self‐healing ability, which makes the bio‐based materials more eco‐friendly. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46272.     

Liquid crystal behavior of cellulose nanoparticles-ethyl cellulose composites: Preparation,characterization, and rheology

This work deals with assessing the approach for preparation of cellulose nanoparticles (CNPs) to be acted as synergistic component in liquid crystal (LC) ethyl cellulose composite (EC-CNPs). In this respect different structures of CNPs were prepared by acid and salt agents. These prepared CNPs were characterized by carboxyl content, IR, transmission electron microscope (TEM), and zeta potential, while their composites with EC were characterized by rheological measurements as a key factor for measuring the critical concentration of LC behavior. The results showed that, the crystallinity of CNPs obtained by ammonium persulfate exceeded that prepared by sulfuric acid hydrolysis. TEM images of stained CNPs showed both methods led to produce nanoparticles have rod like shape with aspect ratio (L/W) between 7.69 ± 3 and 31.3 ± 5. For the rheological measurements, it demonstrated the efficient of incorporating the CNPs to EC (EC-CNPs composites) to decrease the critical concentration of EC from 40 wt% to approximately 34 wt%.     

Bioprinting a cell-laden matrix for bone regeneration: A focused review

Although many efforts have been made to regenerate the bone lesions, existing challenges can be mitigated through the development of tissue engineering scaffolds. However, the weak control on the microstructure of constructs, limitation in preparation of patient-specific and multilayered scaffolds, restriction in the fabrication of cell-laden matrixes, and challenges in preserving the drug/growth factors' efficacy in conventional methods have led to the development of bioprinting technology for regeneration of bone defects. So in this review, conventional 3D printers are classified, then the priority of the different types of bioprinting technologies for the preparation of the cell/growth factor-laden matrixes are focused. Besides, the bio-ink compositions, including polymeric/hybrid hydrogels and cell-based bio-inks are classified according to fundamental and recent studies. Herein, different effective parameters, such as viscosity, rheological properties, cross-linking methods, biodegradation biocompatibility, are considered. Finally, different types of cells and growth factors that can encapsulate in the bio-inks to promote bone repair are discussed, and both in vitro and in vivo achievement are considered. This review provides current and future perspectives of cell-laden bioprinting technologies. The restrictions and challenges are identified, and proper strategies for the development of cell-laden matrixes and high-performance printable bio-inks are proposed.