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Cross‐linked cationic polyvinyl alcohol (CPVA) is obtained by solution polymerization using vinyl acetate (VAc) and N‐(isobutoxymethyl)acrylamide (IBMA) as main raw materials and free radical co‐polymerization using glycidyl methacrylate (GMA) and dimethylaminoethyl methacrylate (DM) as modified monomers. The structure is characterized by HNMR. The effects of DM monomer on the properties of CPVA are investigated. It turns out that CPVA dispersion is a Bingham fluid with good stability. The particle size of CPVA reaches minimum and the value is 147.2 nm, which is in favor of infiltration into the paper. It is more suitable for the DM dosage ranging from 2% to 2.5% in light of the mechanical properties of CPVA film. The obtained CPVA is amorphous and the degree of crystallinity is decreased. When used as surface sizing agent for paper, the water absorption of the sizing paper reaches minimum and the folding resistance reaches maximum when DM is 2.5%. The maximum dry and wet tensile indexes of the paper are increased by 190.71% and 331.09%, respectively. SEM results shows that the larger pores between the paper fibers are filled and cross‐linked after CPVA sizing, which is beneficial to the improvement of paper strength. [ABSTRACT FROM AUTHOR]

Although styrene acrylate emulsions (SAE) have demonstrated promising applications as surface sizing agents for paper, their strengthening effect on pulp fibers in papermaking is not clear. In this study, bagasse fibers, an agricultural waste, were treated with SAE to study the influences on the mechanical properties of the produced papers. SAE copolymers with hard chain (H‐PSA) and soft chain (S‐PSA) were prepared and added to bagasse pulp slurry at concentrations of 1%–4% by weight. The findings indicated that for the soft and hard copolymers, the glass transition temperatures were 19.5 and 26.8°C and their emulsion particle sizes were 166 and 182 nm, respectively. The copolymers strengthened the produced paper by wrapping around and forming a network of chemical and physical bonds with the pulp fibers. Papers treated with 3% H‐PSA exhibited the optimum improvement in tensile strength (38 MPa) and breaking length (67 m) by 13% and 64%, respectively. Treated papers were negatively affected by UV radiation due to phenyl groups spread along the chains. The copolymers demonstrated good wet‐strength properties achieved by self‐ and co‐crosslinked networks. The prepared paper sheets showed a preference for the mechanical properties of treated samples over the untreated ones. [ABSTRACT FROM AUTHOR]

Acid‐catalyzed hydrolysis of glycosidic bonds is the most important degradation mechanism affecting cellulose‐based materials. It results in the decrease of DP and in the loss of the original mechanical properties. The neutralization of acidity is therefore one of the most efficient ways to hamper the degradation of cellulosic artworks. However, in the case of acidic and strongly degraded artifacts, in addition to deacidification, a consolidation treatment must be performed. To this aim, a new class of biopolymers, obtained by a synthetic procedure that considers the principles of Sustainable Chemistry, was investigated. Three allyl saccharide/vinyl acetate copolymers, having different molar ratios between starting monomers, were prepared using α,α'‐trehalose, and used to synthesize the corresponding allyl saccharide/vinyl alcohol copolymers. The use of saccharide derivatives as monomers improves the affinity and compatibility of the biopolymer with the artifacts to be treated. After characterization, the efficacy of the copolymers in the strengthening of degraded paper was evaluated with mechanical tests. The most effective system was thus selected for further testing. Its performance was compared to that of Klucel G®, a commercial product belonging to the class of cellulose derivatives, which are largely used in conservation practice. [ABSTRACT FROM AUTHOR]

To obtain additives that could simultaneously increase the dry strength and wet strength of paper sheets, we synthesized a series of crosslinked cationic glyoxalated polyacrylamide (GPAM) resins by using acrylamide (AM), 2-methacryloxyethyl trimethyl ammonium chloride (DMC), N-methylolacrylamide (NMA), 2-mercaptoethanol, and glyoxal as the main materials. GPAM demonstrated excellent properties and had a good strengthening ability under the following polymerization conditions: dosage of AM = 55 wt %, dosage of the cationic monomer DMC = 5.5 wt %, dosage of the crosslinking monomer NMA = 8.0 wt %, dosage of chain-transfer agent 2-mercaptoethanol = 1.0 wt %, dosage of glyoxal = 30 wt %, and charge of the initiator (ammonium persulfate/sodium bisulfite = 1 : 2) = 0.5 wt %. The products were characterized by Fourier transform infrared spectroscopy, 1H-NMR, size exclusion chromatography, and Ubbelohde viscometry. The copolymers with a viscosity-average molecular weight of approximately 26,000 and a polydispersity index of 1.460 had a much better strengthening ability. When these GPAM resins were used as paper-strengthening agents, the mechanical strength of the paper was remarkably enhanced, and the dry and wet tensile indices of the handsheets increased by 24.6 and 381%, respectively, compared with those of handsheets without GPAM. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012 [ABSTRACT FROM AUTHOR]

Aramid based on poly (p‐phenylene terephthalamide) (PPTA) is widely concerned as high‐performance materials. Herein, copolymerized aramid nanofibers (CANFs) were prepared for the first time by a direct bottom‐up polymerization method without additives. Three kinds of third monomers of m‐phenylenediamine, 4,4′‐diaminodiphenyl ether, and 2,5‐dichloro‐1,4‐phenylenediamine were separately copolymerized in PPTA and transformed into nanofiber dispersions in water medium. The characterization results revealed the relationship between the morphology of products and the structure as well as dosages of the different kinds of monomers, which was explained by the influence on conjugate regularities of the PPTA molecules. Furthermore, CANFs were used to build aramid paper blended in pure PPTA nanofibers, and the mechanical and insulation properties of composite paper were improved significantly, which would be of potential use as the new building block for aramid composite materials. [ABSTRACT FROM AUTHOR]

This study was conducted to assess the effect of the pulping by‐products crude tall oil (CTO), distilled tall oil (DTO), and tall oil fatty acid (TOFA) on dynamic water vapor sorption behavior, interfiber strength, and thermal stability of cellulosic paper‐sheets. The results were compared against those obtained in cellulose papers treated with the conventional petroleum‐derived hydrophobic agent hydrowax and in untreated ones. The tall oil treatments caused strong reduction in equilibrium moisture content of the paper‐sheets during adsorption and desorption runs. The same trend was noticed for the hydrowax‐treated papers, however, it was less pronounced than the CTO‐treated and DTO‐treated samples in the relative humidity range of 75–95%. The sorption hysteresis was considerably decreased after the treatments. The ultimate dry‐tensile strengths of the paper‐sheets were significantly reduced by TOFA and hydrowax treatments, while CTO and DTO showed comparable strength as that of untreated control. The ultimate wet‐strengths of the paper‐sheets were improved after the treatments. The thermal stability of the specimens was improved by the tall oil treatments, and the hydrowax‐treated samples illustrated lower degradation temperature than the untreated control. The results are promising for the use of tall oils as alternative hydrophobic agents of cellulosic fiber‐based products, such as wood panels and paper packaging. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47303. [ABSTRACT FROM AUTHOR]

This paper focuses on the calculation of the interfacial tension of two systems: low‐density polyethylene with isotactic polypropylene and high‐density polyethylene with syndiotactic polypropylene. For this, three methods to measure the interfacial tension are compared: the use of Palierne's model, and Gramespacher and Meissner's model, both based on additional elasticity or long relaxation times brought by shape recovery of dispersed phase, and ab‐initio calculation, which requires the knowledge of the surface tension of the neat polymer measured at the same temperature. For that, a database collected from the literature is built in the first section of this paper, whether for the studied systems or for other systems of various olefinic homopolymers or copolymers with polypropylene. The results show the effectiveness of the Gramespacher and Meissner's model to calculate the interfacial tension of the studied systems for which the results were in agreement with ab‐initio calculation and Palierne's model. Extension of the ab‐initio calculation to olefinic copolymers was proposed. [ABSTRACT FROM AUTHOR]

Wood is an irreplaceable structural and biodegradable material, which is subject to swelling, shrinkage, significant deformation of structural elements, and products when its moisture content changes. This paper proposes wood surface modification with reactive copolymers based on glycidyl methacrylate and alkyl methacrylates to impart superhydrophobic properties with initial contact angles up to 166°. Scanning electron microscopy and energy dispersive X‐ray spectroscopy were used to study the features of polymer coating formation and to determine the modifier penetration depth, which was more than 1000 μm. It has been shown that copolymers do not fill the initial capillary system of wood. Modified wood is characterized by stable water‐repellent properties with low‐water diffusion rates, with the water absorption rate reduced by more than three times compared to that of initial wood. Polymer coatings provide water repellency, retain the appearance of original wood, and provide increased buoyancy. [ABSTRACT FROM AUTHOR]

In this paper, a new kind of environmental friendly double‐network gel material was prepared. The first network structure was formed by the graft copolymerization of sodium lignosulfonate (LS) and acrylic acid (AA), and the second network structure was formed by the chelation reaction of sodium alginate (SA) and carbide slag clarified solution (Ca2+). Through an orthogonal experiment, the effects of raw material addition on the compressive strength and apparent viscosity of the gel were analyzed. According to the analysis results, the optimal experimental ratio was obtained, i.e., 2 wt% of LS, 0.25 wt% of SA, 15 wt% of AA, 0.1 wt% of MBA and 0.3 wt% of APS. Furthermore, the structure of the gel are characterized by FTIR, XRD, SEM, XPS, and TG‐DTG, and the results prove that the gel successfully polymerized and a stable three‐dimensional network structure is formed. The results of water absorption experiment disclose that the gel is sensitive to ions and pH, and the water absorption rate reaches 121.25 times. In addition, the results of the air leakage experiment and fire extinguishing experiment show that the gel can effectively cover the surface of crushed coal and densely fill the gaps, demonstrating a good plugging capability and fire extinguishing capability. [ABSTRACT FROM AUTHOR]

Polyacrylamide (PAM) microsphere has been widely used in the field of profile control to reduce water cut in heterogeneous reservoirs. However, its mechanical strength and plugging ability are still needed to be improved. In this paper, a core‐shell structure and surface‐hydrophobic polyacrylamide M‐P(AM‐PEP) microsphere was prepared by using acrylamide (AM), block polyether macro monomer (PEP) and modified SiO2 with double bond on the surface as monomers through dispersion polymerization. After the optimization of synthesis conditions, the results of SEM and TEM confirmed that M‐P(AM‐PEP) microsphere had the nano‐scale spherical shape and the inorganic core/polymer shell structure, while the contact angle test results showed that M‐P(AM‐PEP) microsphere had the surface‐hydrophobicity. Swelling experiments presented that the size of M‐P(AM‐PEP) microsphere can be increased by 6 times and had obvious self‐gathering behavior. The inorganic core and self‐gathering behavior are helpful for improving mechanical strength and plugging ability of PAM microsphere, respectively. Profile control and oil recovery improvement experiment showed that injecting 0.1 PV M‐P(AM‐PEP) microsphere can decrease the water cut and increase the oil recovery of 17.95%. This new microsphere could be an efficient technology for the profile control in the heterogeneous reservoir. [ABSTRACT FROM AUTHOR]

In this paper, a series of poly(ethylene terephthalate‐co‐2,6‐naphthalate) (PETN) (co)polyesters with different naphthalene ring contents were synthesized via a two‐step transesterification and polycondensation. The effects of the monomer compositions on the sequence distribution, crystallization, mechanical, thermal, and barrier properties of the (co)polymers were investigated systematically. The results showed that the introduction of naphthalene ring units (NDC) changed the sequence length of the PETN and disrupted the orderly arrangement of the PETN molecular chains, thus affecting the aggregated structure and properties of the copolymer. When the NDC content was less than 30%, the PETN copolymers displayed good ductility and higher yield strength comparable to PET, and the heat distortion temperature (HDT), thermal stability properties, and barrier properties of the copolymer were also improved. In addition, the diffusion kinetics of water and oxygen molecules in the (co)polymer were investigated by the MS program simulation software. The differences in gas barrier properties of the different PETN (co)polymers were explained at the molecular level. This study provides a systematic theoretical basis and comprehensive practical guidance for the preparation of high‐performance copolyester materials. [ABSTRACT FROM AUTHOR]

A novel nanocomposite leather‐finishing agent (denoted as H‐TiO2@SDS‐rGO/F‐PBMA) composed of fluorinated copolymer (denoted as F‐PBMA) matrix using methyl methacrylate (abbreviated as MMA), butyl acrylate (abbreviated as BA) as well as acrylic acid (abbreviated as AA) as monomers and H‐TiO2@SDS‐rGO composite nanoparticles as nano‐additives were successfully fabricated by aqueous emulsion polymerization in this paper. The hollow TiO2 nanoparticles (denoted as H‐TiO2) were firstly prepared with tetrabutyl titanate as titanium source wall and tetraethyl silicate as silicon source core through an alkali etching method, and then they were compounded with reduced graphene oxide (rGO) modified by sodium dodecyl sulfate (denoted as SDS‐rGO) for obtaining H‐TiO2@SDS‐rGO composite nanoparticles. Fourier transform infrared spectra, X‐ray diffraction, Raman spectra, scanning electron microscopy, and nuclear magnetic resonance spectra were used to characterize the structure and morphology of different samples. The experimental results reveal that the nanocomposite leather‐finishing agent not only has excellent transparency, but also endows sheepskin better weather resistance, thermal stability, hydrophobicity and mechanical properties compared with traditional leather finishing agents. [ABSTRACT FROM AUTHOR]

Microplastic has become the focus of environmental pollution recently, especially in seawater. Due to its high crystallinity and hydrophobicity, the degradation rate of poly(butylene succinate) (PBS) is slow. In this paper, a series of poly(butylene succinate‐co‐diethylene glycol succinate) (PBSD) copolymers were synthesized by melt‐polycondensation in order to improve the nonenzymatic hydrolysis of PBS. The contact angle and water uptake content of copolymer were increased obviously when the regular crystalline structure of chain segment was disturbed by diethylene glycol. Rheological tests revealed the microphase separation structure occurred at 130°C. The tensile strength of PBSD40 copolymer was 15 MPa and the elongation at break was more than 700%, and the decomposition temperature was above 370°C. The weight loss of PBSD60 copolymer in acid condition was 98.6% after 49 days at 50°C. However, in neutral condition and simulated seawater, the weight loss was less than 10%. Acid and alkaline catalyzed the hydrolysis of ester bonds. Some holes and cracks appeared at the surface of the samples after degradation from SEM analysis. Thus, PBSD copolymers have the potential to serve as promising water degradable materials. [ABSTRACT FROM AUTHOR]

Large bone defects due to accidental injuries and fractures as well as the mismatch between the implant material and the defect site are major problems in biomedicine. Bone tissue engineering offers a solution to this problem. In this paper, a series of three‐dimensional porous composite scaffolds with shape memory were prepared using polycaprolactone and polytetrahydrofuran as soft segment materials, hexamethylene diisocyanate as hard segment materials and amorphous calcium phosphate/calcium citrate (CAP) as inorganic fillers. The scaffolds have tunable mechanical properties, melt temperature, surface wettability, a pore size range of 100–800 μm and a high degree of connectivity. In vitro mineralization showed good mineral deposition and energy dispersion spectrometer displayed uniform distribution of Ca and P elements on the surface. The composite scaffold exhibited good shape memory properties at 37°C. The shape fixation rate (Rf) and shape recovery rate (Rr) were maintained at 94.1% and 94.4% after five compression cycles. The resulting scaffold promoted MG63 cell proliferation to some extent. The scaffold is expected to be used clinically for the treatment of large bone defects. [ABSTRACT FROM AUTHOR]

For a probe tack test for a pressure‐sensitive adhesive (PSA) under the conditions of light contact pressure and short contact time, probes with shapes and surface roughnesses suitable to achieve better wettability were investigated. A smooth, polished probe that became slightly convex at its center was found to be superior to flat‐ended. High surface roughness decreased tack. Debonding observations showed that fibrillation started from the probe edge and extended to the center. The fibril grew, without peeling, until the peak of the force–displacement curve was reached. After the peak, the fibril growth and peeling advanced simultaneously. The fibrillation was important to tack development. The test conditions necessary to observe the deformation behavior of PSA tape with sufficient interfacial adhesion were investigated. The system was preheated at 60°C for 1 h after the probe and PSA tape contacted each other, and was then cooled. The PSA performance of crosslinked random copolymers poly(n‐butyl acrylate‐acrylic acid) (A) and poly(2‐ethylhexyl acrylate‐acrylic acid) (B) were compared. A shoulder formed by fibrillation after the peak in the force–displacement curve was observed only for B. Copolymer B exhibited better interfacial adhesion and deformability. The preheating method was found to be useful for characterizing PSAs. [ABSTRACT FROM AUTHOR]

As the development of oilfield exploitation, more and more oil in water (O/W) emulsion was produced, thus efficient reverse demulsifier becomes increasingly important. In this paper, a series of novel reverse demulsifiers (R‐PED1 ~ 4) with the characteristics of polyacrylate and polycation were prepared. The structure of the product was verified by IR specter and 1H NMR. The thermal stability was studied with TGA and the molecular weight was obtained by GPC. Field evaluation results showed that the oil content in produced liquid after R‐PED4 treatment can be reduced from 1550 to 81 mg/L at R‐PED4 dosage was 50 mg/L. Furthermore, the demulsification mechanism of R‐PED was discussed. The R‐PED has good surface/interfacial activity. It can effectively reduce the oil–water interfacial film strength and reduce the zeta potential of oil droplets, which is beneficial for the coalescence of oil droplets. Especially, the interaction force between oil droplets was measured by the optical tweezers. R‐PED4 can increase the attraction force between oil droplets. Consequently, the contact time of oil droplets during the demulsification process can be prolonged and the coalescence of oil droplets also can be effectively promoted. The novel reverse demulsifier offers a new option for the oilfield produced liquid treatment. [ABSTRACT FROM AUTHOR]

Succinic acid is an important synthetic monomer but it is difficult to use it as a precursor for synthesizing high molecular weight polyamide, due to its tendency to perform intra‐cyclization reaction at high temperature. In order to solve this problem, in this paper, the direct solid‐state polymerization (DSSP) method with the initial reactant, nylon salt which was composed of 1, 5‐diaminopentane, succinic acid, and terephthalic acid, was applied to synthesize the bio‐based copolyamide PA 5T/54. In comparison with the conventional melting polymerization method, the DSSP method can prevent the cyclization reaction of succinic acid effectively due to the lower reacting temperature as well as the restriction effect of the nylon salt. As a result, the product fabricated by DSSP method has higher molecular weight and much lighter color from red to white. Therefore, the DSSP method is advantageous for the synthesis of the polymers or copolymers composed of the succinic acid as the monomer. Furthermore, the polymerization mechanism proposed in this work can serve as a guidance for the design of the molecular structure and control of the polymerization process. [ABSTRACT FROM AUTHOR]

Copolymerization of cationic monomer and nonionic macromonomer in water‐ether mixture solution is useful for preparing the functional polymer. Copolymer of diallyldimethylammonium chloride (DMDAAC) and a nonionic block polyether macromonomer (PEP‐65) has been found that has very well reverse demulsification performance, but the polymerization phenomenon cannot be described by any reported polymerization method. In this paper, the copolymerization behavior including polymer mechanism, polymerization kinetics, and reactivity rate of DMDAAC and PEP‐65 in the mixture solution of water and propylene glycol methyl ether (PGME) was studied for explaining the special copolymerization phenomenon and its flotation performance for treating oily wastewater was also investigated. The results showed that DMDAAC‐PEP‐65 copolymerization in water‐PGME mixture solution has four stages and has both characteristics of emulsion polymerization and dispersion polymerization. In addition, the copolymer also has excellent flotation performance. [ABSTRACT FROM AUTHOR]

The structural changes in the hydrolyzed polyacrylamide (PAM) under different saline conditions show significant effects on the rheological properties. At the higher shear rates, these conformational changes cannot be discerned in the shear rheological field but the extensional rheology can probe the polymer's microstructure can provide a better description. In this paper, two types of polymers: co‐hydrolyzed PAM and post‐hydrolyzed PAM were tested under different saline conditions. The polymer conformation results were interpreted to ascertain the underlying mechanisms of polymer and cation interactions and their effect on the extensional properties. The results showed that the interactions of polymer chains with divalent cations lead to the formation of the cross‐linked chelating structures corresponded to the narrow molecular weight distribution (MWD) with a lower radius of Gyration (Rg). However, the uniform carboxylate ion density across the co‐hydrolyzed PAM restricted shrinkage of the polymer chains after interactions with cations showed the high strain hardening due to polymer chain entanglement at high Hencky strain. Whereas, monovalent cation interactions with the carboxylate groups resulted in the monodentate structures that sustained the broader MWD that explains the observed higher strain hardening and extensional relaxation time. [ABSTRACT FROM AUTHOR]

ABSTRACT In this paper, a hydrophobic monomer (HM) that has a cationic double alkyl-substituted group bonded to the nitrogen atom was first synthesized. Then a hydrophobic poly(vinyl alcohol) (PVA) was prepared by a radical solution copolymerization of vinyl acetate (VAc) with the HM followed by an alcoholysis reaction in alkaline conditions. The structures of HM and hydrophobically modified PVA (H-PVA) were confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance. The effect of hydrophobic cationic segments on crystallization behaviors, mechanical properties, morphology, solution viscosity, and hydrophobic property were investigated. The results indicated that the crystallinity decreased from 37.2% of pure PVA to the minimum 23.2% of H-PVA with the incorporation of 1.15 mol % HM. The thermal decomposition temperature of H-PVA increased by about 50 °C compared with that of pure PVA. The viscosity of the H-PVA solution was several times higher than that of the corresponding unmodified PVA solution over the whole shear rate range, which demonstrated that the H-PVA had good shear-resistance ability. Furthermore, the contact angle was significantly increased from 55.1° to 115° with the incorporation of only 0.83% HM, which illustrated that the H-PVA had high hydrophobicity. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43888. [ABSTRACT FROM AUTHOR]

Considering the inadaptability of traditional anodic bonding to polymer materials, the flexible anodic bonding process is developed. The bonding characteristics of the dynamic intelligent electric fields with the low‐temperature plasma surface treatment to polymer and ultrasonic‐assisted preconnection before bonding are very suitable for the anodic bonding of polymer elastomer to aluminum (Al) sheet. A series of composite polyurethane elastomer cathode materials (CPECs) with good bonding properties are prepared and characterized. The highest ionic conductivity of CPECs can reach to 2.7 × 10−3 S/cm (CPEC2) at 75°C. After bonded, it is determined that a uniform and dense intermediate bonding layer showed by SEM is formed between CPECs and Al. In addition, different elements including C, O, F, S, and Al are clearly identified by EDS in the bonding layers, showing that the process of flexible anodic bonding has accompanied the directional migration of ions. The maximum tensile strength of bonding layer for CPEC2 and Al (CPEC2‐Al) is up to 2.03 MPa. It is proven that the developed flexible anodic bonding can effectively improve the joint quality and reliability for polymer elastomer materials. All these results of anodic bonding are more potentially valuable to the packaging of flexible devices. [ABSTRACT FROM AUTHOR]

ABSTRACT With increasing demand for ecological leather, ecological fatliquors with good comprehensive properties are getting more and more attention. The amphiphilic acrylate copolymer containing both hydrophilic (carboxyl) and hydrophobic (long alkyl) groups is one of the main alternatives to conventional fatliquors. In this paper, a series of poly(acrylic acid -co-stearyl acrylate) with different relative molecular weights were prepared, and the influence of the molecular weight on their application performances were evaluated. The results show that lower relative molecular weight of copolymers is conducive to the penetration and absorption, and it improves the softness and fiber separation of leather. When the number average molecular weight ( Mn) of copolymer is higher than 25,000, its penetration and absorption become worse and the resulting leather feels hard. In addition, the amphiphilic acrylate copolymers can impart excellent oxidation resistance and transference resistance to leather, which is a considerable improvement over the conventionally retanned and fatliquored leather. The copolymer has great penetration and absorption ability when Mn is within the range of 9,000-15,000, and it gives leather excellent integrated properties, such as filling, softness, mechanical strength, extraction resistance, and oxidation resistance, which can meet requirements of ecological leather. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43440. [ABSTRACT FROM AUTHOR]

ABSTRACT Recently, efforts have been devoted to find ways in utilizing biomass as feedstocks for the production of organic chemicals. This is because of its abundance, renewability and worldwide distribution. Lignocellulosic agricultural waste materials are regarded as abundant, inexpensive, and readily available natural resources for both chemical and paper industries. Hydrogels are polymeric materials that vary in their origin and composition and can absorb large amount of water without dissolving. In our study, cellulose-based acrylic acid hydrogel was synthesized starting from rice straw as a source for the lignocellulosic material, where cellulose was first isolated after alkaline-acid pulping treatment followed by bleaching step with sodium hypochlorite resulting of 90.8% holocellulose. The cellulose-based acrylic acid hydrogel was synthesized applying heterogeneous reaction and shows a swelling ratio more than 3000%. The resulting hydrogel was further characterized with FT-IR and SEM. On the other hand, comparison between the rice straw-based hydrogel and the commercially available acrylamide hydrogel was studied for improving maize production in salt affected soil as well as in the growth promoters of maize under water stress. The experimental results demonstrated that the yield parameters were increased with increasing irrigation rates. Both types of hydrogels introduce positive and significant effect compared to the one without adding hydrogels. Also, acrylamide hydrogel was effective for improving almost yield parameters more than applying rice straw-based hydrogel. Generally, the addition of hydrogel increases the nutrient concentration, uptake, and both of water and nutrients use efficiency. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42652. [ABSTRACT FROM AUTHOR]

ABSTRACT Polyvinylpyrrolidone (PVP) grafted sulfated polysaccharide of the seaweed Cystoseira indica (CIsps) (CIsps- graft-PVP) was synthesized in aqueous medium under microwave irradiation in the presence of potassium persulfate (KPS), as a free radical initiator. Varying the reaction parameters, e.g., concentration of PVP and KPS, reaction time and temperature, optimum grafting condition was identified as the one having the highest grafting ratio (Gr 2.30) and grafting efficiency (Ge 0.92). The grafted copolymer was characterized by FT-IR, 13C-NMR and thermo gravimetric analysis (TGA). The 5% (w/v) dispersion of the new material CIsps- graft-PVP in water exhibited comparable binding properties with papers, polyethylene sheets, and wood pieces as against that of a commercial adhesive. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42383. [ABSTRACT FROM AUTHOR]

ABSTRACT Phase separation of block copolymer films is a perspective technique for the creation of nanostructured templates. The phase separation can be induced by thermal or vapor solvent annealing. However, a standardized and reproducible technique of the phase separation is still missing, even though many papers describing various experimental conditions. In this article we have tried to develop standardized and reproducible technique of the phase separation, which can be easily scaled up. For this purpose we used the combination of the thermal and vapor annealing of poly(styrene-b-4-vinylpyridine) copolymer films on a glass substrate under static conditions. The technique was tailored by the choice of optimal solvent for the vapor annealing, based on the solvent-polymer interaction. Finally, the films were reconstructed by immersing in methanol or ethanol and stretching of the P4VP component during the reconstruction was investigated by the angle-resolved X-ray photoelectron spectroscopy. Morphology of the films was investigated by the atomic force microscopy and confocal microscopy. The kinetics of the phase separation was also studied. The presented combined technique of the thermal and vapor annealing can be easily temperature-controlled for reproducibly obtaining the films of a desired morphology. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41853. [ABSTRACT FROM AUTHOR]

ABSTRACT In moisture wicking fabrics, fibers with hydrophilic surfaces that are also non-water soluble are desirable. In poly(lactic acid), PLA, fibers it is expected that the addition of poly(ethylene glycol), PEG, will monotonically increase their wicking rates. In this paper, phase separation was used to create biocompatible, biodegradable, hydrophilic yet non-water soluble fibers by electrospinning PLA with PEG and PLA-b-PEG copolymers. By tuning the thermoelectric parameters of the apparatus, and the chemical properties of the dopes, the amount of PEG in the fibers was improved over prior work; concentration increased by 60% (by weight, wt %) to 16 wt % in the PLA fiber. Instead of the expected increasing wicking rates with PEG concentration, there is a peak at 12 wt %; at greater concentrations, wicking decreases due to PEG crystallization within the PLA (verified via DSC). At 12 wt % PEG from copolymers, the nanofabric's wettability increases to 1300% its original weight. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41030. [ABSTRACT FROM AUTHOR]

In this paper, we reported a new method to fabricate CdTe quantum dots (CdTe QDs), which were synthesized in aqueous solution using thioglycolic acid and L-phenylalanine ( L-Phe) as costabilizing agent. Then, they were transferred into organic phase with the assistance of cetyltrimethylammonium bromide (CTAB) for further utilization. Finally, we use toluene diisocyanate as a bridge between CdTe QDs and polyacrylate (CPA), whose side chain has hydroxyl group, to synthesize a fluorescent composite polymer CdTe-CPA. In addition, we synthesized an organic substance 4-[2,4-di( tert-butyl)]phenoxy- N-(2-hydroxyethyl)-1,8-naphthalimide (N), and obtained 1,8-naphthahmide fluorescent polymer N-CPA in the same way as it did on CdTe-CPA. The resulting materials were characterized by Fourier transform infrared spectroscopy (FT-IR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), transmission electron microscope (TEM), and photoluminescence (PL). Then, we studied the fluorescence resonance energy transfer (FRET) between CdTe-CPA and N-CPA. The data obtained from absorption and fluorescence emission spectral indicated that the FRET from N-CPA to CdTe-CPA could be efficiently triggered in the solution of chloroform. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

This report describes the application of a recently developed polyolefin characterization tool based upon gradient adsorption high-temperature liquid chromatography (HT-LC) using a graphitic carbon stationary phase to polyolefin homopolymer and previously unreported copolymer systems. Polyolefin-based materials find utility in a broad range of applications and are differentiated by parameters such as molecular weight and comonomer content. Polymer comonomer distribution is commonly determined by crystallinity-based separations (ATREF, CRYSTAF). These techniques, however, are time consuming. In addition, some semicrystalline polymers undergo cocrystallization, impacting the techniques' universal utility. Adsorption-based HT-LC can ideally overcome the limitations of crystallinity-based separations, shedding new light on the composition of randomly-polymerized polyolefins. In this report the basic separation capability of the adsorption HT-LC technique, using a graphitic carbon column, is demonstrated for poly (ethylene- co-octene) and poly(ethylene- co-propylene) systems and compared with select precipitation/redissolution HT-LC and ATREF results. Select results in this paper are also compared and contrasted to other recent publications on similar separations of polyolefins. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 [ABSTRACT FROM AUTHOR]

In this article, a novel poly‐(acrylic acid‐acrylonitrile) (PAA‐AN)/filter paper composite membrane with pH‐sensitivity was developed. The membrane was composed of three layers. The top and bottom layers were made of PAA‐AN copolymer, while the middle layer was filter paper. The filter paper was used to enhance the strength of the membrane. The PAA‐AN/filter paper membrane showed evident pH sensitivity and pH reversibility as the pH value changed between 2.0 and 9.5. With the increase of the PAA‐AN copolymer amount in the composite membrane, the pH sensitivity increased. The Cu (II) ion‐exchange experiment indicated that the membrane could bind metal ions and could be used as ion‐exchange membrane to purify water. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 [ABSTRACT FROM AUTHOR]

Eucalyptus Kraft lignin was blended in various proportions with two different types of polyethylene (PE) (low‐density polyethylene and post‐consumer recycled [PCR]), with or without compatibilizer (PE‐glycidyl methacrylate [GMA] or PE‐2‐hydroxyethyl methyl acrylate copolymers). Materials prepared by injection molding or extrusion casting were characterized for their thermal, antioxidant, antibacterial and mechanical properties. In addition, the photo‐permeability was assessed, as this property is specifically relevant to mulching applications. The use of compatibilizers enhanced the antioxidant properties which reached more than 3 h oxidation induction time when lignin was present at 20 wt% and beyond. Good antibacterial properties were obtained on Gram‐positive bacteria when using PE‐GMA as compatibilizer. The photo‐permeability of the materials was also reduced, reaching a transmittance lower than 5% throughout the whole measurement range (200–800 nm) in PCR. However, higher lignin contents led to a more brittle material and the overall processability of the material became more difficult, features that were not improved by compatibilizers. These materials are promising candidates for mulching film application, especially with PCR which still lacks high‐volume market applications. [ABSTRACT FROM AUTHOR]

This study discusses the synthesis of sulfonated amine block copolymers and the effect of multiple ionic domains and counter‐ion substitution on polymeric membranes' morphology and transport properties for chemical protective clothing (CPC) applications. The monomers 2‐(tert‐butylamino) ethyl methacrylate, 2‐ethoxy ethyl methacrylate, and styrene were used to prepare the block copolymers by atom transfer radical polymerization (ATRP). The copolymers were then sulfonated by chemical grafting with pendants sulfobutyl groups onto the polymer structure. Properties of the resulting membranes were evaluated as a function of block composition, incorporation of sulfonic groups, and counter‐ion substitution. Blended membranes with sulfonated poly(styrene‐isobutylene‐styrene) (SIBS) were also studied. A series of materials characterization techniques (e.g., Fourier‐transform infrared spectroscopy [FT‐IR], thermogravimetric analysis [TGA], atomic force microscopy [AFM], Small‐angle X‐ray scattering [SAXS]/wide‐angle X‐ray scattering [WAXS]) were performed to describe the changes to the membranes. The results indicate that synthesized copolymers lack phase segregation mainly because of a low sulfonation on the central amine block, leading the material to have a low Water/DMMP selectivity. As the sulfonated copolymers were blended with SIBS 75, the breathability of the membranes were enhanced 1.5 times, and almost all candidates achieved the water vapor transport rate limit of 1500 g m−2 day−1. Finally, the better‐found candidates for DMMP CPC were Mg2+ membranes, achieving selectivity between 20 and 90 range. [ABSTRACT FROM AUTHOR]

To improve the flame retardancy of PA6/PA66 copolymer, a phosphorus‐nitrogen flame retardant DDP‐M was successfully synthesized via melt condensation reaction between 2‐[(5‐oxo‐6H‐phosphanthridin‐5‐yl)methyl]butanedioic acid (DDP) and melamine (Mel). Its structure, product composition, and thermal stability were characterized by FTIR, nuclear magnetic resonance spectroscopy (NMR), matrix‐assisted laser desorption and ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS), and thermogravimetric analysis (TGA). The results suggested that DDP‐M was a hybrid flame retardant. A series of flame‐retardant PA6/PA66 composites were prepared by melt extrusion. Their thermal stability and flame retardancy were assessed by differential scanning calorimetry (DSC), TGA, limiting oxygen index (LOI), and vertical burning test (UL‐94). The combustion behavior demonstrated that DDP‐M can effectively improve flame retardancy, achieving 32% of LOI value and UL‐94 V‐0 rating with only 9 wt.% addition. No melt dripping was accomplished by adding 12% DDP‐M. The high dose (15%) harmed the flame‐retardant properties. The results of pyrolysis gaseous productions analysis and residual carbon analysis revealed the flame‐retardant mechanism of DDP‐M was a synergistic effect of melamine inducing gaseous phase flame retardancy and highly condensed P‐N char layers inducing condensed phase flame retardancy. The composites retained good mechanical properties due to the good dispersibility and compatibility between polyamide and DDP‐M. [ABSTRACT FROM AUTHOR]

Improving the mechanical properties of hydrogels is a prime example of their large‐scale, diverse applications. Herein, we report a one‐pot method for preparing a double network system hydrogel where the polyvinyl alcohol served as the first polymer backbone, acrylamide as the second network, and N, N′‐Methylenebisacrylamide as the cross‐linker, and the prepared hydrogels presented excellent mechanical properties with 1168% tensile strain and 598 kPa compressive strength. Through the metal–ligand bonds, an electrolyte solution containing Cu2+ was introduced into the hydrogel, which exhibits higher water retention than other electrolyte‐containing hydrogels. Specially, the hydrogel was able to retain water for 8 h under extreme dry conditions at 60°C. The GF value was calculated to be 0.124 when the strain was 0%–64.2%. Furthermore, the hydrogel flexible sensor can detect changes in ambient temperature. When the ambient temperature rises, its relative resistance also tends to rise. In conclusion, this hydrogel sensor offers great potential applications in flexible sensors. [ABSTRACT FROM AUTHOR]

A series of reactive copolymers with peroxide functionality (RCPFs) were synthesized via radical copolymerization of monomer mixtures in an organic solvent comprised of a peroxide monomer 5‐(tert‐butyl peroxy)‐5‐methylhex‐1‐en‐3‐yne, acrylamide, maleic anhydride, and butyl methacrylate. Peroxide functionality allows the RCPFs to initiate a variety of radical processes, including cross‐linking of organic polymers. Hydrophilic monomer subunits (acrylamide and maleic anhydride) within the RCPF macromolecules promote cross‐linking of water‐soluble polymers. We aimed to investigate RCPF comonomer ratio and its effects on copolymerization kinetics and composition, as well as physico‐chemical and colloidal properties. We also evaluated and characterized the kinetic parameters of the thermal decomposition of peroxide moieties in the synthesized RCPF. Findings revealed that RCPF possessed surface‐active properties and reduced surface tension at its aqueous solution–air interface. The data indicated that the decomposition process complied with the first‐order kinetics, and complex thermal analysis confirmed the presence of peroxide moieties. RCPFs' ability to cross‐link water‐soluble polymers was demonstrated on poly(acrylamide) and poly(vinyl alcohol). [ABSTRACT FROM AUTHOR]

The removal efficiency of an anionic acid dye, Acid Orange 10 dye (AO‐10), and hexavalent chromium metal Cr(VI) from an aqueous medium using carboxymethyl xanthan gum‐g‐poly(4‐vinyl pyridine), CMX‐g‐P(4VP), as a novel adsorbent was studied. The influences of pH, adsorbent dose, temperature, and equilibrium time on the adsorption process were evaluated to optimize the conditions for maximum removal of the adsorbate. Both AO‐10 and Cr(VI) removal were pH‐dependent, with the most excellent adsorption capacity occurring at pH 2.5. AO‐10 and Cr(VI) had maximum adsorption capacities of 1961 and 492 mg g−1, respectively, considerably high. The adsorbent may be efficiently reused for five cycles, according to the desorption studies. The experimental adsorption equilibrium data were described using the Langmuir, Freundlich and Dubinin‐Radushkevich isotherm models. The Langmuir is judged the closest to the description of the practical. In addition, the kinetics of the adsorption process is controlled using pseudo‐first‐order and intraparticle diffusion kinetic models, while the thermodynamic process proved the spontaneous and exothermic nature of removing AO‐10 and Cr(VI) ions. Overall, the results showed that CMX‐g‐P(4VP) might be a very efficient re‐usable adsorbent in wastewater treatment. [ABSTRACT FROM AUTHOR]

Carboxylated styrene‐butadiene latex (XSBL), attributed to its insufficient adhesion and poor water resistance, cannot be widely popularized in the adhesive industry. Herein, a novel XSBL‐based resin with high‐strength yet water‐resistant was reported, in which the butadiene macromolecular chains were grafted with acrylonitrile (AN) and acrylic acid‐2 hydroxyethyl ester (HEA) molecules, the crosslinking sites were esterified and expanded to construct a branched network structure, and the matrix was filled with nano‐SiO2 particles treated by blending silane coupling agents. We show that the new resin, having a dual curing mechanism at low and high temperatures, can be glued under different conditions. At room temperature, the sample group with a doping level of 1.33 wt% could achieve an overload shear strength of 3.17 MPa after curing, which is 233.7% higher than the XSBL; in the high temperature curing regime, the glue strength reached 1.21 MPa, much higher than the standard for the use of GB Class I plywood (≥0.7 MPa). The physicochemical properties meet the requirements for potential industrialization, for which the property–structure relation has been extensively explored. Further DSC and TG tests provide evidence for their wide application in the hot pressing process of man‐made plywood. [ABSTRACT FROM AUTHOR]

The aim of this study was to develop temperature and pH‐responsive biodegradable 3D printed drug‐releasing constructs using the Digital Light Processing (DLP) printing technique. The printable molecules, named "inks" throughout this study, comprised polyethylene oxide–polypropylene oxide–polyethylene oxide (PEO–PPO–PEO) triblocks and acrylic acid (AAc) that rendered them reverse thermo‐responsive (RTR) and pH‐sensitive, respectively. Additionally, the inks' biodegradability was imparted to them by incorporating lactide (LA) and ε‐caprolactone (CL) units into their composition, while their printability was achieved by end‐capping them with 2‐Isocyanatoethyl methacrylate (IEMA). By fine tuning the LA/CL composition, a broad range of inks displaying different water absorption behavior, biodegradation as well as bovine serum albumin (BSA) release profiles at different conditions. All the hydrogels showed a fast and reversible swelling–deswelling response, as they fluctuated between pH 2.0 and pH 7.4 or between 10 and 37°C. The resultant hydrogels showed good water uptake capacity (6340%) at pH 7.4 and 10°C temperature. BSA release from the loaded 3D printed hydrogel showed a maximum (80.5%) at pH 7.4 and 10°C in comparison to pH 7.4 and 37°C (65%). The proposed dual responsive 3D printed biodegradable hydrogels objects will shed light as a drug carrier. [ABSTRACT FROM AUTHOR]

Biobased co‐polyesters poly(butylene succinate‐co‐butylene furandicarboxylate) (PBSF) is prepared by transesterification and polycondensation of dimethyl succinate (DSMu), dimethyl 2,5‐furandicarboxylate (MDFD) and 1,4‐butanediol (1,4‐BDO). GPC analysis shows that PBSF has high molecular weight with weight average molecular weight (Mw) up to 11 × 104 g/mol. Due to the low ‐COOH content, PBSF also has excellent thermal stability, which is beneficial to the polyester processing. Differential scanning calorimetry (DSC) analysis shows that PBSF are semi‐crystalline materials, with Tm ranging from 116 to 101°C. Tensile tests showed that theses polymers possess high tensile strength (30–22 MPa) and elongation at break as high as 562%, which is prominently higher than that of commercial poly(butylene succinate) (PBS) and most biodegradable packaging materials. It should be noted that the increase of BF units improves the UV shielding properties of polyester materials. Moreover, the incorporation of furan ring promoted the enzymatic degradation of PBS, and PBSF showed a significantly faster biodegradation rate when the BF unit content is 5%. PBSF polyester has excellent thermal properties, tensile properties, UV shielding properties and biodegradable properties. Therefore, these new bio‐based polymers have great potential to be applied as environmentally friendly and sustainable plastic packaging. [ABSTRACT FROM AUTHOR]

ABSTRACT A novel bio-based and flame-retardant UV-curable vinyl ester resin (VER) monomer named Diglycidyl ester of maleinized dipentene modified with dibutyphosphate and methacrylic anhydride (MDDMD) was synthesized from industrial dipentene via Diels-Alder reaction, glycidylation, epoxy ring-opening reaction, and esterification. Its chemical structures were characterized by Fourier transform infrared (FTIR) analysis and proton nuclear magnetic resonance (1H-NMR). In order to improve its flexibility, we prepared a series of copolymers under UV light radiation by mixing it with certain proportions of poly(ethylene glycol) dimethacrylate-200 (PEGDMA-200) which contained flexible groups. Their tensile property, curing degrees (CD), hardness, limiting oxygen index (LOI), dynamic mechanical thermal properties, and thermostability were all investigated. The cured mixed resins have a relatively high tensile strength of 10.05 MPa and curing degrees up to 92.5%. Both hardness (range: 50 to 23 HD) and LOI (range: 22.8% to 24.4%) of cured resins are improved with the increase of MDDMD content. Dynamic mechanical analysis (DMA) shows that their glass transition temperatures rise with the increase of MDDMD content. Thermogravimetric analysis (TGA) shows that the thermal stability of cured resins is enhanced with the increase of PEGDMA-200 content, as the main thermal initial decomposition temperatures are all above 260 °C and char yield at 800 °C are above 18.10%. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44084. [ABSTRACT FROM AUTHOR]

Two block copolymers with poly(silylene acetylenearyleneacetylene) (PSA) as block A and polydimethylsiloxane (PDMS) as block B have been synthesized by Grignard reagent. The structure and properties of the copolymers have been studied. The chopped T700 carbon fibers have been used to reinforce the copolymers to obtain the composites. The ablation and change of composition on the surface of composites have been further investigated. The results show that there are two block structures of ethynyl‐endcapped copolymers. The copolymer with ABA structure (PPSOA‐1) is solid at room temperature, and the other with BAB structure (PPSOA‐2) is viscous. The thermal stability of the cured PPSOA‐1 is higher than that of the cured PPSOA‐2. The chopped T700 carbon fibers reinforced copolymer composites keep shape well after 300 s at 600°C in a muffle furnace and maintain above 91% weight retention. Under the heat flow of 1 MW m−2, there are white inorganic layers on the surface of the composites after ablation in 120 s at 1200°C. The white layer on the T700CF reinforced PPSOA‐1 composite is hollow and composed of amorphous carbon‐containing silica. The block copolymer of PDMS‐co‐PSA with excellent thermal stability is promising for utilization in thermal protection systems. [ABSTRACT FROM AUTHOR]

Due to biocompatibility and similar extracellular matrix structure, polyvinyl alcohol (PVA)/polyethylene oxide (PEO) nanofiber membranes are an essential medical dressing. However, the phase separation of the PVA/PEO composite system will occur within a short time. It severely limits the continuous preparation of PVA/PEO nanofiber membranes. To make PVA/PEO composite system maintain compatibility, a novel polyvinyl alcohol‐allyl polyethylene glycol (PVA‐g‐APEG) graft copolymer with phase change, compatibilization and biocompatibility was prepared successfully. Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) prove that the copolymerization and alcoholysis reaction allyl polyethylene glycol (APEG) and vinyl acetate (VAc) successfully obtained PVA‐g‐APEG graft copolymer. The prepared PVA‐g‐APEG not only has electrospinability but can effectively prevent the phase separation of PVA/PEO composite system, which ensures the continuity of electrospinning in the industry. Additionally, the feasibility of the PVA‐g‐APEG compatibilized PVA/PEO composite system for application in biomedical was verified through the preparation and various assessments of PVA‐g‐APEG/PVA/PEO nanofiber dressings. The prepared PVA‐g‐APEG is beneficial to the PVA/PEO composite system to broaden its application in biomedical and other fields. [ABSTRACT FROM AUTHOR]

To explore more efficient heavy metal copper ions adsorbents with double network polymers, this work has presented the novel fabrication processes of the polymer composite diatomaceous earth/polydopamine‐polyethyleneimine/alginate DE@PDA‐PEI@SA, which was characterized by FT‐IR, SEM, EDS, XPS, and was efficiently utilized for copper ions adsorption. The relevant adsorption behaviors of DE@PDA‐PEI@SA for copper ions such as the effect of pH, the effect of adsorbent dosage, adsorption kinetics, adsorption isotherm etc. have been investigated. The results reveal that the adsorption kinetics of DE@PDA‐PEI@SA for copper ions at different temperatures can be modeled by the pseudo second‐order rate equation, the experimental data fit well with the Langmuir isotherm model, indicating a homogeneous monolayer adsorption, and the maximum adsorption capacity of DE@PDA‐PEI@SA for copper ions could reach 454.55 mg/g at 35°C that is very high compared to other reported adsorbent materials. The research results indicate that DE@PDA‐PEI@SA is a novel efficient adsorbent with high efficiency in wastewater treatment and water purification, which could provide a facile processing for copper adsorption. [ABSTRACT FROM AUTHOR]

The demand for highly‐durable protective coatings for use in extreme environments is continually growing, however, poor durability and adhesion restricted their practical applications. Herein, we prepared a novel solution‐processable graphene‐based copolymer for fabricating highly‐durable protective coatings. The random‐structured copolymer GO‐g‐(PMMA‐co‐PMPS) was prepared by graphene‐based initiator (GO‐g‐Cl) initiating methyl methacrylate (MMA) and 3‐methacryloxypropyltrimethoxysilane (MPS) via surface‐initiated atom transfer radical polymerization (SI‐ATRP). The copolymers rendered the coatings with high transmittance (~95%), high hydrophobicity (water contact angles = 113.8 ± 2.13°), and strong adhesion (1.26–1.38 MPa). Tetrahydrofuran (THF)‐casted coating surface presented a higher Si content and greater surface roughness than that cast from dimethyl carbonate (DMC), yielding more hydrophobic coating than those cast from DMC. The coatings could be coated on different substrates (glass, aluminum, and sandstone); and besides, the structures and performance of the coatings remained unchanged, even exposing to acid/alkali, salt, and ultraviolet light irradiation. These high‐performance properties make the GO‐based copolymers ideal candidates for fabricating high‐durability protective coatings. [ABSTRACT FROM AUTHOR]

In this work, a thermo‐responsive hydrophobically associative water‐soluble terpolymer was prepared and evaluated as polymer flooding in laboratory tests versus a heavy crude oil from a carbonated reservoir in southern Mexico. Terpolymer of acrylamide, N‐isopropylacrylamide and N,N′‐dihexylacrylamide were synthesized via micellar free radical polymerization. Reaction was carried out at 50°C using sodium dodecyl sulfonate as surfactant and 4‐(4′‐azobis)cyanovaleric acid as initiator. The terpolymer was characterized by nuclear magnetic resonance. Steady shear viscosity of polymer solutions at different concentrations was determined in the presence of NaCl (from 1 to 5 wt%) at different temperatures (from 25 to 120°C). Heavy crude oil sample was characterized and revealed a viscosity of 2. 26 Pa s, 10.21° API with a content of Saturates, Aromatics, Resins, Asphaltenes of 26.4, 38.5, 22.3, and 12.8, respectively. The crude oil recovery of polymer at 2 and 3 wt% revealed a surface tensions of 49.6 and 48.2 mN × m and adsorption capacities of 1.33 and 1.77 wt%. Finally, polymer solutions at 2 and 3 wt% showed a contact angle between 29.6 and 26.5° and a crude oil recovery of 68.3 and 75.3%, respectively. [ABSTRACT FROM AUTHOR]

Although acrylic acid‐based superabsorbent hydrogels (SAHs) are widely used in hygiene and personal care applications, the low degrees of true ionization in such SAHs under practical application places a limit on the degree of superabsorbency that can be achieved. Herein, the preparation and optimization of SAHs based on copolymers of acrylic acid (AA) with 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS), a strong acid comonomer that remains ionized at all relevant physiological pH values, is described. AA‐AMPS recipes optimized using a central composite design response surface method demonstrate significantly enhanced absorbance under load (AUL) values (>15–20% increase) and comparable centrifuge retention capacity (CRC) values compared to the corresponding AA‐only controls while maintaining strong mechanics even in the swollen state (as much as twice the modulus of the commercial AA‐based superabsorbent). The simplicity of this recipe, coupled with the reproducible achievement of the improved superabsorbency properties using a small adaptation of the commercial SAH synthesis protocol, makes AA‐AMPS superabsorbent hydrogels potential candidates for use in commercial hygiene products. [ABSTRACT FROM AUTHOR]

We synthesized an acrylic acid 4‐[(10‐oxo‐10H‐9‐oxa‐10λ5‐phospaphenanthren‐10‐yl)‐phenylamino‐methyl]‐phenyl ester (DOPO‐AC), a novel Schiff base derivative based on 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide, and evaluated its utility as a flame retardant for polystyrene (PS). The synthesized DOPO‐AC was characterized by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance spectroscopy, and high‐resolution mass spectrometry. The reactive vinyl groups of DOPO‐AC further copolymerized with styrene to produce PS/DOPO‐AC. Thermogravimetric analysis showed that DOPO‐AC could clearly improve the char residue formation. By comparing the data of T5% and T10%, it was found that the thermal stability of the PS/DOPO‐AC copolymer was reduced. We investigated the influence of DOPO‐AC on the flame retardancy of PS by determining limiting oxygen indexes, conducting vertical burning tests (UL‐94), and carrying out thermogravimetry combined with differential thermal analysis. These results revealed that PS containing 5 wt% DOPO‐AC had a UL‐94V‐0 rating and a limiting oxygen index of 29.6%. Residues of PS/DOPO‐AC copolymer after the UL‐94V tests were analyzed by scanning electron microscopy, X‐ray photoelectron spectroscopy, and FTIR spectroscopy; and the results allowed us to propose a flame retardant mechanism for PS/DOPO‐AC copolymer. Taken together, our results prove that DOPO‐AC is an effective flame retardant for PS. [ABSTRACT FROM AUTHOR]

Polypropylene (PP) is an affordable plastic commodity but lacks massive use in engineering applications given its limited mechanical properties including significantly low impact strength. In this work, three polyolefin‐based copolymers including ethylene‐octene random block (Engage, E), ethylene‐octene multi‐block (Infuse, I), and ethylene‐propylene copolymer (Versify, V) were blended with PP. It was found that the V copolymer was miscible while the rests were immiscible in the PP matrix. Mechanical testings indicated that the addition of the 20% E and 20% I copolymers significantly enhanced the impact toughness of PP up to 83% and 108% at −20°C, respectively. At a higher temperature such as 25°C, the impact toughness of the PP/E20 and PP/I20 were 400 and 571%, respectively. The enhancement of the PP impact toughness was governed by the particle size of the added immiscible copolymers. Experimental results also revealed that the good compatibility between PP and copolymers has an insignificant influence on the mechanical properties of PP while the essence of added copolymer plays a key role instead. The findings from this work provide significant insights into the design of PP‐based products with desirable properties to satisfy requirements demanded by engineering applications. [ABSTRACT FROM AUTHOR]

Influences of subphase pH value and ionic strength (NaCl concentration) on the aggregation behavior of a symmetric diblock polyelectrolyte poly(n‐butyl acrylate)‐block‐poly(acrylic acid) (PnBA‐b‐PAA) at the air/water interface and its Langmuir–Blodgett (LB) films were studied. With the increase of subphase pH value, surface pressure–molecular area isotherms of PnBA‐b‐PAA monolayers shift toward smaller area due to the gradually enhanced ionization and underwater solubility of hydrophilic PAA chains. All the initial LB films transferred from different subphases with/without NaCl (before monolayer compression) exhibit the densely mixed structures of worm‐like aggregates and circular micelles, which indicates that the aggregate formation belongs to the spontaneous mechanism. The micelle core diameters in the LB films increase with the increase of subphase pH value, owing to the enhanced PAA chain solubility and PnBA block aggregation. Under acidic condition, micelle cores are slightly larger upon addition of NaCl due to the enhanced underwater solubility of the uncharged PAA chains triggered by their possible interaction with Cl−. Under neutral/alkaline conditions, micelle cores are also larger upon addition of NaCl, which is attributed to the electrostatic shielding effect of Na+. Upon compression, the LB films prepared under neutral/alkaline conditions exhibit the predominantly large circular micelles. [ABSTRACT FROM AUTHOR]

Surface migration of unmodified inorganic or polymer core‐inorganic shell nanoparticles has limited their application for improvement of pressure‐sensitive adhesives (PSAs) properties. The efficiency of utilization of modified inorganic nanoparticles with sticky polymer brushes was investigated to overcome this problem. For this purpose, polymethacryloxypropylsilsesquioxane‐acrylic core‐shell (CS) nanoparticles were synthesized and added to poly(methyl methacrylate‐co‐butyl acrylate) (MBC) acrylic PSA through latex blending. Using CS nanoparticles, a concomitant increase in the peel and shear strengths of the acrylic PSA was achieved, and also the limitation of surface migration of nanoparticles at high volume fractions was overcome. Moreover, CS nanoparticles acted as a compatibilizer for MBC chains, rich in methyl methacrylate (MMA) or butyl acrylate (BA). These MMA‐rich and BA‐rich chains were formed during the synthesis of MBC latex through batch emulsion copolymerization method, due to the difference in the reactivity ratio of BA and MMA radicals. The compatibility of CS nanoparticles with each of the components of MBC was systematically investigated in terms of grafting density, swelling ratio, and thermodynamic affinity and was correlated to the final properties. [ABSTRACT FROM AUTHOR]

Biodegradable polymers are important in medical applications including absorbable medical devices and drug delivery systems. Copolymerization is an effective approach to extent the diversity of biodegradable polymers with combined certain properties of each components. In order to receive biodegradable polymers possess both advantages of poly(l‐lactide) and poly(p‐dioxanone), a series of biodegradable poly(l‐lactide‐co‐p‐dioxanone) (P(LLA‐co‐PDO)) copolymers with random and block architectures were synthesized via one‐step or two‐step ring‐opening polymerizations of L‐lactide (LLA) and p‐dioxanone (PDO) monomers in the presence of stannous octoate [Sn(Oct)2]. The compositions of PDO in random copolymers were much lower than those in feeding doses, implying low reactivity of PDO in the copolymerization. The molecular weights of PPDO segments and the ratios between PPDO and LLA were the key factors to affect the compositions of PLLA‐PPDO‐PLLA triblock copolymers in two‐step polymerization. The thermal, mechanical and degradation properties of the copolymers were investigated. The amorphous and semi‐crystalline P(LLA‐co‐PDO) copolymers are potentially utilized in biomedical applications. [ABSTRACT FROM AUTHOR]