Radical Solution Polymerization Research Articles

Synthesis and Evaluation of Poly (Trifluoroethyl Methacrylate) Binders as a Polyvinylidene Fluoride Alternative for Lithium‐Ion Batteries

The binder, a critical electrode component, significantly influences lithium‐ion batteries (LIB) performance, yet remains an under‐researched area. The widespread use of polyvinylidene fluoride (PVDF) as a commercial binder is challenged by its surging cost, attributed to limited production and increased demand, highlighting the necessity for alternatives. Here, we synthesize poly (trifluoroethyl methacrylate) (PTFEMA), a polymer with a molecular weight in the million range, through a straightforward radical solution polymerization method, aiming to use it as a cathode binder for LIBs. PTFEMA demonstrate good stability across the typical operating temperatures and voltages, along with robust adhesion to the current collector. Moreover, the PTFEMA outperforms PVDF in terms of electrolyte affinity and lithium‐ion conductivity, thereby achieving capacity and stability comparable to those of its PVDF counterparts. This investigation confirms the homopolymer form of PTFEMA as a compelling alternative to PVDF, representing a valuable exploration of binder technology for LIBs.

Effect of sodium 2‐acrylamido‐2‐methylpropanesulfonate on the structure and properties of thermoplastic polyvinyl alcohol copolymers

AbstractThermoplastic poly(vinyl alcohol) (PVA) with water‐soluble behavior has received great attention. In this work, a thermoplastic PVA was prepared via solution radical polymerization of vinyl acetate, vinyl pivalate and sodium 2‐acrylamido‐2‐methyl propane sulfonate (SAMPS). The effects of SAMPS content on the structure and properties of modified poly(vinyl alcohol) (MPVA) were investigated. On increasing the proportion of SAMPS, the characteristic band of –OH moved to a larger wavenumber. Compared to PVA, the melting temperature (Tm) of MPVA decreased from 223.1 to 161.5 °C at 0.03 mol of SAMPS, and the initial thermal decomposition temperature (Td) of MPVA increased from 244.3 to 262.2 °C at 0.05 mol of SAMPS. The crystallinity of the resin reduced from 51.46% to 10.21%. The enlarged difference between Td and Tm ensured the preparation of MPVA by thermal processing. The maximum tensile strength and elastic modulus of the obtained sheets were 137.56 and 2639.32 MPa, respectively. The introduction of SAMPS reduced the alcoholysis degree from 99.03% to 95.80%. The high alcoholysis degree of MPVA meant that it could be dissolved in water at 60 °C. This type of thermoplastic PVA shows a promising application on film and textiles that require water solubility. © 2024 Society of Chemical Industry.

Effects and Mechanism of Hyperbranched Phosphate Polycarboxylate Superplasticizers on Reducing Viscosity of Cement Paste.

The adsorption behavior and dispersing capability of hyperbranched phosphated polycarboxylate superplasticizers (PCEs) containing phosphate monoester and phosphate diester were investigated. The hyperbranched structures were constructed using a special monomer dimethylaminoethyl methacrylate (DMAMEA) to create the branches during the polymerization. Meanwhile, the polymer architectures were tailored by varying the content of phosphate monoester and phosphate diester in the backbone via free radical solution polymerization. In contrast to comb-like PCE, hyperbranched PCEs presented a weaker dispersion capability at w/c = 0.29, but with a lower water-to-cement ratio (w/c), the hyperbranched PCEs exhibited a better dispersion capability than the comb-like PCEs. The dynamic light scattering (DLS) and transmission electron microscope (TEM) analysis showed that the adsorption layer of hyperbranched PCEs were thicker than that of comb-like PCEs. A thicker adsorption layer thickness generated thinner diffusion water layer thickness. The increase of the free water amount due to the thinner water diffusion layer is the key mechanism for improving the dispersibility and decreasing the viscosity of cement paste.

Comparative Analysis of Hydrogel Adsorption/Desorption with and without Surfactants.

In this particular study, a hydrogel known as SAP-1 was synthesized through the grafting of acrylic acid-co-acrylamide onto pullulan, resulting in the creation of Pul-g-Poly (acrylic acid-co-acrylamide). Additionally, a sponge hydrogel named SAP-2 was prepared by incorporating the surfactant sodium dodecyl benzene sulfonate (SDBS) into the hydrogel through free radical solution polymerization. To gain further insight into the composition and properties of the hydrogels, various techniques, such as Fourier transform infrared spectroscopy, hydrogen nuclear magnetic resonance (1H NMR), atomic absorption spectroscopy, and field emission scanning electron microscopy (FE-SEM), were employed. Conversely, the absorption kinetics and the equilibrium capacities of the prepared hydrogels were investigated and analyzed. The outcomes of the investigation indicated that each of the synthesized hydrogels exhibited considerable efficacy as adsorbents for cadmium (II), copper (II), and nickel (II) ions. In particular, SAP-2 gel displayed a remarkable cadmium (II) ion absorption ability, with a rate of 190.72 mg/g. Following closely, SAP-1 gel demonstrated the ability to absorb cadmium (II) ions at a rate of 146.9 mg/g and copper (II) ions at a rate of 154 mg/g. Notably, SAP-2 hydrogel demonstrated the ability to repeat the adsorption-desorption cycles three times for cadmium (II) ions, resulting in absorption capacities of 190.72 mg/g, 100.43 mg/g, and 19.64 mg/g for the first, second, and third cycles, respectively. Thus, based on the abovementioned results, it can be concluded that all the synthesized hydrogels possess promising potential as suitable candidates for the adsorption and desorption of cadmium (II), copper (II), and nickel (II) ions.

Facile Synthesis of Poly(methyl methacrylate) Silica Nanocomposite Monolith by In Situ Free Radical Polymerization of Methyl Methacrylate in the Presence of Functionalized Silica Nanoparticles.

Novel porous poly(methyl methacrylate) (PMMA) silica nanocomposites have been produced by utilization of polymerization-induced phase separation in a simple one-pot approach. A facile free radical polymerization of MMA in the presence of surface methacrylate-functionalized silica nanoparticles was carried out in ethanol-based solvents, successfully producing novel, morphologically designable porous nanocomposite monoliths. Differing from standard free radical polymerization in solution, a mixture of good and poor solvents (ethanol/N,N-dimethylformamide ratio) for the resulting polymer was used to trigger spinodal phase separation. The influence of monomer concentration, as well as solvent composition, on the morphology of the resulting porous polymers has been investigated. Porous monolith structures composed of connected particles and co-continuous morphologies were observed under a scanning electron microscope depending on the polymerization conditions. The resulting polymers were insoluble and showed swelling characteristics in some organic solvents that are capable of dissolving regular PMMA, indicating covalent bonds between the functionalized silica nanoparticles and the polymer chains. The presence of silica particles in the final polymer was proven via an ATR-IR analysis. The glass transition temperature of the present PMMA-silica nanocomposite was higher than that of the conventional PMMA. The porous polymer immersed in a mixed organic solvent showed coloration induced by the Christiansen effect.

Poly(acrylamide)-co-poly(hydroxyethyl)methacrylate-co-poly(cyclohexyl methacrylate) hydrogel platform for stability, storage and biocatalytic applications of urease

In our present work, an explicit crosslinked thermo-responsive hydrogel platform has been developed, by using polyacrylamide (PAAm), poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(cyclohexyl methacrylate) (PCHMA), and then coupled with urease to yield bioconjugates (BCs). Synergic effect of these polymer units provides thermoresponsive nature, optimum crosslinking with desired swelling behaviour, and stability and improved catalytic to Urease in the resultant BCs. Synthesis of the terpolymer has been achieved by employing HEMA (monomer as well as crosslinker), instead of using the conventional crosslinkers, through free radical solution polymerization technique. Various grades of TRPUBs have been fabricated by varying HEMA and CHMA contents while keeping fixed amounts of AAm. Further, the structural analysis of BCs has been done by fourier transform infra-red spectroscopic study and their thermal stabilities have been studied by thermogravimetric analysis. Urea present in TRPUBs has beenanalysed for its hydrolysis atdifferent temperatures viz., 25 °C, 45 °C and 70 °C. Further, the effect of crosslinking, temperature and reaction time on catalytic activities of TRPUBs has been studied. TRPUBs grades have showna maximum swelling capacity up to 5200 %; excellent catalytic activity even at 70 °C; and 85 % activity retention after 18 days storage in buffer medium.

Synthesis and characterization of n-isopropylacrylamide based copolymers with silver nanoparticles

In recent years, the so-called "smart" polymers, which can systematically respond to small environmental changes, such as pH, temperature and electric field, are widely used in many fields. Researchers are particularly interested in using drugs to transport to the right place in the human body. One of the types of these smart polymers are thermosensitive polymers. Among the thermosensitive polymers, the most well-known are homo- and copolymers based on N-isopropylacrylamide. In the research work, in order to improve the properties of thermosensitive polymers, silver nanoparticles were added to the hydrogel composition. Hydrogels based on N-isopropylacrylamide and 2-hydroxyethylacrylate monomers were synthesized by radical polymerization in solution (in H2O and AgNO3 solution). While the production of silver nanoparticles is based on the redox (by NaBH4 solution) mechanism, the formation of these nanoparticles in the gel was carried out by diffusion. While the introduction of silver nanoparticles into the gel was controlled by ultraviolet spectroscopy, its inclusion in the gel was confirmed using a scanning electron microscope (SEM). Meanwhile, a hydrogel containing silver nanoparticles exhibits antibacterial properties, it was investigated using biomedical tests. It has been shown here that a hydrogel containing silver has good antibacterial properties, whereas a hydrogel without silver does not have the ability to destroy bacteria.

Polymer-laponite composites as filtrate reducer for high temperature and salt resistant drilling fluid: Characterization and performance evaluation

In deep and ultra-deep well drilling, ultra-high temperatures and high salt lead to poor drilling fluid performance. In this study, N, N-dimethylacrylamide (DMAA), dimethyldiallylammonium chloride (DMDAAC), 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS), 4-acryloylmorpholine (ACMO) and modified laponite (m-LAP) were polymerized into polymer nanocomposites PDADA-LAP by free radical polymerization in aqueous solution. The structure of PDADA-LAP was characterized by FT-IR, 1H NMR and XPS. The microstructure of PDADA-LAP was characterized by TEM, SEM and EDS. The results showed that LAP improved the network structure of the polymer by hydrogen bonding and covalent bonding. The effect of temperature on the degradation of the polymer solution was investigated. The experiment showed that the degradation temperatures of the polymer was 220 °C. PDADA-LAP was used as a filtrate reducer in drilling fluids. The results showed that 3.0 wt% PDADA-LAP could improve the filtration performance of drilling fluids at high temperature of 220 °C and resist contamination with 20 wt% NaCl. The FLAPI and FLHTHP were 7.0 mL and 28.6 mL, respectively. PDADA-LAP is adsorbed on bentonite particles through hydrogen bonding and electrostatic interaction, which slows down the contamination of bentonite particles by NaCl and gives the drilling fluid a good effect to reduce fluid loss at high temperature and high salt.

Synthesis, characterization, and swelling properties of a novel tapioca-g-Poly(Acrylic acid−2−acrylamido−2−methylpropane sulfonic acid)/ammonium polyphosphate superabsorbent polymer

In this study, a novel superabsorbent polymer tapioca starch-g-poly(acrylic acid-2-acrylamido-2-methylpropane sulfonic acid)/ammonium polyphosphate (TS-g-AA-AMPS/APP) was synthesized based on the graft copolymerization of tapioca starch (TS) with acrylic acid (AA) and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) via free radical polymerization in aqueous solution with ammonium polyphosphate (APP) additive added for study. The synthesized superabsorbent polymer material was characterized by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), energy-dispersive x-ray spectroscopy (EDS), and thermogravimetric analysis (TGA). Research investigating the material synthesis conditions to absorbance in distilled water and 0.9 wt% NaCl solution has also been studied. Under optimal synthesis conditions, the absorbance in distilled water and 0.9 wt% NaCl solution were 416 g g−1 and 61 g g−1, respectively, for the sample with 3 wt% APP content. The introduction of APP units has improved the absorption properties of the material such as the water retention capacity reaching 55.25% in 10 h at 60 °C. TS-AA-AMPS/APP exhibits reversible swelling ability, with the swelling level not being reduced compared to the initial after 5 swelling-drying cycles at 60 °C, and water absorption reaches swelling equilibrium after about 270 min. Additionally, TGA thermogravimetric analysis results showed an improvement in the thermal stability of TS-AA-AMPS/APP compared to the pure polymer. These results show that the TS-AA-AMPS/APP polymer with excellent swelling properties, low production cost, and environmentally friendly has the potential for practical applications in agriculture, gardening, and water retention materials.

The synthesis and adsorption-dispersion properties of PPEGMA-PVPA copolymers in cement paste.

This study reports the synthesis of a novel superplasticizer, poly(poly(ethylene glycol)methacrylate)-poly(vinylphosphonic acid) (PPEGMA-PVPA), containing phosphate moieties via solution radical polymerization. By adjusting the feed ratios of monomers, PPEGMA-PVPA copolymers with different phosphate group densities were obtained, and their chemical structure was characterized via FT-IR, 1H NMR spectroscopy and ICP-OES. The results demonstrated that about 70% of the VPA monomer was polymerized. The thermostability of PPEGMA-PVPA was also determined through DSC and TGA. The adsorption-dispersion performance onto cement pastes was investigated using mini-slump test, TOC and zeta potential analysis. It was demonstrated that the adsorption capacity of PPEGMA-PVPA onto cement paste was about 1.4 times stronger than that of the reference polycarboxylate superplasticizer and exhibited excellent adsorption-dispersion performance.

Synthesis and performance of novel fluoro acrylate polymer containing rigid cyclohexane group as a mesogenic core

Fluorine-containing liquid crystal polymers have excellent hydrophobic stability, making them attractive for use in the field of stable hydrophobic coatings. To improve the hydrophobic stability of fluoropolymers, a novel fluoro acrylate monomer (FAM) containing a rigid cyclohexane structure was simply synthesized using isophorone diisocyanate (IPDI), hydroxyethyl methacrylate (HEMA), and perfluorohexylethanol (S104) as raw materials and its homopolymer (PFAM) was prepared by radical solution polymerization. The structure, liquid crystal behavior, thermal properties, hydrophobic properties, and surface properties of FAM or PFAM and a reference substance, dodecafluoroheptyl methacrylate (DFMA) and its homopolymer (PDFMA), were studied using various techniques including FT-IR, NMR, GPC, XRD, POM, DSC, TGA, XPS, AFM, and static/dynamic contact angle measurements. The results indicate that FAM and PFAM are thermally liquid crystalline. PFAM's thermal stability is higher than that of PDFMA. The presence of a rigid cyclohexane structure facilitates the dense distribution of fluorocarbon chain tails of the homopolymer and also prevents surface reconstruction when the homopolymer comes into contact with polar liquids, resulting in improved hydrophobicity and hydrophobic stability. Thus, this study provides a straightforward method for the synthesis of fluoro acrylates with surface stability, highlighting their potential application in hydrophobic coatings.

Efficacious adsorption of divalent nickel ions over sodium alginate-g-poly(acrylamide)/hydrolyzed Luffa cylindrica-CoFe2O4 bionanocomposite hydrogel

Existing Ni2+ heavy metal ions in an aqueous medium are highly hazardous for living organisms and humans. Therefore, designing low-cost adsorbents with enhanced effectiveness is essential for removing nickel ions to safeguard public health. In this study, a novel green nanocomposite hydrogel was synthesized through the free radical solution and bulk polymerization method, and its capability to remove divalent nickel ions from aqueous media was examined. The bionanocomposite hydrogel named as SA-g-poly(AAm)/HL-CoFe2O4 was produced by grafting polyacrylamide (AAm) onto sodium alginate (SA) in the presence of a magnetic composite recognized as HL-CoFe2O4, where HL represents hydrolyzed Luffa Cylindrica. By employing FT-IR, XRD, VSM, SEM, EDX-Map, BET, DLS, HPLC, and TGA techniques, morphological evaluation and characterization of the adsorbents were carried out. The performance of the adsorption process was studied under varying operational conditions including pH, temperature, contact duration, initial concentration of pollutant ions, and adsorbent dosage. HPLC analysis proved the non-toxic structure of the bionanocomposite hydrogel. The number of unreacted acrylamide monomers within the hydrogel matrix was measured at 20.82 mg/kg. The optimum conditions was discovered to be pH = 6, room temperature, adsorbent dosage of 1 of g.L−1, initial Ni2+ concentration of 10 mg.L−1, and contact time of 100 min, and the maximum adsorption efficiency at optimal state was calculated as 70.09, 90.25, and 93.83 % for SA-g-poly (AAm), SA-g-poly(AAm)/HL, and SA-g-poly(AAm)/HL-CoFe2O4 samples, respectively. Langmuir isotherm model was in good agreement with the experimental data and the maximum adsorption capacity of SA-g-poly(AAm), SA-g-poly(AAm)/HL, and SA-g-poly(AAm)/HL-CoFe2O4 samples was calculated to be 31.37, 43.15, and 45.19 mg.g−1, respectively. The adsorption process, according to kinetic studies, follows a pseudo-second-order kinetic model. Investigations on thermodynamics also demonstrated that the process is exothermic and spontaneous. Exploring the interference effect of co-existing ions showed that the adsorption efficiency has decreased with concentration enhancement of Ca2+ and Na+ cations in aqueous medium. Furthermore, the adsorption/desorption assessments revealed that after 8 consecutive cycles, there had been no noticeable decline in the adsorption effectiveness. Finally, actual wastewater treatment outcomes demonstrated that the bionanocomposite hydrogel successfully removes heavy metal pollutants from shipbuilding industry effluent. Therefore, the findings revealed that the newly fabricated bionanocomposite hydrogel is an efficient, cost-effective, easy-separable, and green adsorbent that could be potentially utilized to remove divalent nickel ions from wastewater.

Evaluation of newly copolymers and their montmorillonite nanocomposite as cold flow improver for petroleum lubricating oil

The great demand on the energy makes the attention toward modifying lubricating oil. This work tends to prepare the following copolymers; octadecylmethacrylate-co-dodecene (CP1) and octadecylmethacrylate-co-hexadecene (CP2) by free radical solution polymerization using laboratory prepared octadecylmethacrylate monomer with either 1-dodecene or 1-hexadecene. The same monomers also used to prepare their polymers nanocomposite (NP1, NP2) with 1% of nanomontmorolonite by emulsion polymerization. The structures of the prepared polymers and their nanocomposite were elucidated by FTIR, 1HNMR, TGA, DSC, TEM and DLS. These polymers were used as pour point depressant, flow improver and viscosity modifier and showed high efficiency. After comparison of the data of the polymers and their nanocomposite, the nanocomposite give the best results where the pour point decreased from 0 °C to − 18, − 27, − 24 and − 33 °C for CP1, CP2, NP1 and NP2 respectively at the optimum concentration 10,000 ppm. On the other hand the viscosity index increased from 86.57 to 93.25, 92.41, 94.17 and 93.103 for CP1, CP2, NP1 and NP2 respectively, the apparent viscosity increased from 55.863 to 69.31, 119.41, 111.28, and 166.89 cP also the yield stress increased from 652.19 to 1076.3, 1074 and 1480 D/cm2 for CP1, CP2, NP1 and NP2 respectively.

INVESTIGATION OF PHYSICOCHEMICAL AND THERMAL PROPERTIES OF CLAY-HYDROGEL COMPOSITES

Hydrogels are cross-linked polymeric networks which retain large amounts of water. The hydrogels with response capability to various stimuli such as pH and temperature have received great attention in many fields. In this study, hydrogels were synthesized by free radical solution polymerization through optimization of acrylamide/sodium acrylate mole ratio and ethylene glycol dimethacrylate content. With the addition of sepiolite as filler into the hydrogel network which had highest swelling percent, hydrogel composites were obtained. In the presence of 10 wt% sepiolite, maximum swelling percent was determined as approximately 10600%. Swelling properties of the hydrogel composite including 10 wt% sepiolite was investigated depending on pH, salt effect and temperature. With increasing pH value, swelling percent of the hydrogel composite showed an increase. At high temperatures, the hydrogel composite exhibited higher swelling percent. Swelling tests in 0.1 M NaCl, CaCl2 and FeCl3 solutions revealed that the lowest swelling percent was observed in 0.1 M FeCl3 solution. Fourier transform infrared spectroscopy (FTIR) analyses verified successfully preparation of the hydrogel composites. Regular layers of the sepiolite in the hydrogel network which made water diffusion easily were shown by scanning electron microscopy (SEM) analyses. Thermogravimetric analyses (TGA) indicated that thermal stability of the hydrogel network was increased with the addition of sepiolite.

Flexible and Photo-responsive superwetting surfaces based on porous materials coated with Mussel-Inspired Azo-Copolymer

The decoration of porous materials with stimulus-responsive polymers is an efficient strategy for the fabrication of superwetting surfaces; however, the weak interfacial interaction between the polymers and the substrates limits their application. Herein, inspired by the molecular structure of the mussel foot protein, a series of catechol-functionalized azobenzene-containing copolymers with diverse chain structures are synthesized via solution radical polymerization and used for the preparation of smart superwetting surfaces. After dip-coating with the mussel-inspired azo-copolymers, the modified cotton fabrics and melamine sponges possessed smart surfaces with photo-switchable wettability. These as-prepared flexible smart surfaces exhibited rapid wettability transition between high hydrophobicity and superhydrophilicity with alternating ultraviolet (UV) and visible light irradiation. Meanwhile, these superwetting surfaces were also experimentally found to be robust without apparent degradation in their photo-responsiveness, even after being soaked in acid/base solutions and subjected to repetitive mechanical deformation. Especially, the functionalized melamine sponges as bulk superwetting materials have excellent mechanical stability, which can tolerate harsh abrasion cycles and repetitive compressive deformations. More importantly, it was also confirmed that the mussel-inspired azo-copolymers exhibited excellent adhesion properties at the interface of various substrates. This bioinspired strategy and developed functional copolymers paves the way for facile and large-scale fabrication of superwetting surfaces, which may find a wide range of advanced potential applications in microfluidic devices, biomedicine and sensors.

N-PMI modified PAZ nanocomposite coatings with self-healing function for anticorrosion and antifouling applications

With the rapid development of the modern industrial marine economy, metal corrosion and biological fouling of marine ships and engineering equipment have become the main problems affecting the development of the marine industry. Traditional single-function coatings have only anti-corrosion or anti-fouling properties, which cannot meet the current needs of marine industry development for coating protection. In this study, a self-healing coating with good anticorrosion and antifouling properties has been prepared upon functionalization of a film forming resin and modification of a nanofiller. Initially, a modified acrylic resin (PAZ/N-PMI) was successfully synthesized by inserting zinc ions and a structural functional monomer (N-phenyl maleimide; N-PMI) into the polymer chain of an acrylic resin using free radical solution polymerization. A fluorinated silica coated hydroxylated multi-walled carbon nanotubes nanocomposite (F-MWCNTs-OH@SiO2) was dispersed in PAZ/N-PMI resin to prepare the composite coating samples. The composite coating showed good performance, in which the antibacterial rate of the composite coating against Staphylococcus aureus and Escherichia coli was >99.98 %. When F-MWCNTs-OH@SiO2 was 3 wt%, the Zf=0.01Hz of the composite coating reached the highest value, which was 3 orders of magnitude higher than that of the PAZ/N-PMI coating. At the same time, the prepared composite coating also exhibited good self-healing properties. This study provides a broad application prospect for the development of high quality marine anti-corrosion and anti-fouling organic coatings.

Comparative Study between a Copolymer Based on Oleic Acid and Its Nanohybrid for Improving the Cold Flow Properties of Diesel Fuel.

The as-synthesized copolymer based on the prepared monomers and its nanohybrid were used for improving the cold flow of diesel fuel that has a vital role in meeting energy needs. The copolymer (AE) was created using the prepared monomers, by free radical solution polymerization of the prepared hexadecylmaleamide and octyloleate ester, and the polymer nanohybrid (NH) was created by emulsion polymerization of the same monomers with 1% nano-SiO2. The chemical structures of the copolymer and its nanohybrid were proved by Fourier transform infrared spectroscopy (FTIR), 1H NMR, dynamic light scattering (DLS), and transmission electron microscopy (TEM). Through exploring the effect of the nanohybrid, before and after adding the dosage of the additives to the diesel fuel, the pour point temperature (PPT), rheological characteristics, and viscosity index were measured. The data were the best for the nanohybrid; the PPT decreased from -3 to -36 °C upon adding 10,000 ppm nanohybrid but decreased from -3 to -30 °C for 10,000 ppm copolymer. In addition, the efficiency of the additives was proved by viscosity-shear rate and shear rate-shear stress curves to give the apparent viscosity, which decreased from 124 cP for the blank to 15.74 and 12.8 cP for AE and NH, respectively; also, the yield stress decreased from 576 D/Cm2 for the blank to 541.44 and 477.9 D/Cm2 for AE and NH, respectively, at room temperature. The viscosity index increased from 116 for the blank to 119 and 121 for the copolymer and the nanohybrid, respectively. Polarizing optical microscopy was performed to show more tiny and separated wax upon adding the additives. The findings showed that delayed crystal precipitation and altered crystal shape with the NH and AE greatly reduced low-temperature viscosity and enhanced the cold flow characteristics of the diesel fuel.

The influence of poly(maleic anhydride - co - vinyl acetate) on polylactide/wood flour/calcium carbonate composites

In this paper, polylactide (PLA)/wood flour (WF)/calcium carbonate (CC) composites with different content of poly(maleic anhydride -co- vinyl acetate) (PMAVA) were prepared. PMAVA was obtained by radical solution polymerization and identified by FTIR. The torque - time curves showed that the balance torques of PLA/WF/CC composites with PMAVA were improved by the adding of PMAVA. SEM photographs showed that after the addition of PMAVA, the compatibility and interfacial adhesion between the filler (CC or WF) and PLA in each composite were increased. DSC heating curves showed that two cold crystallization temperature (Tcc) peaks appeared in each PLA/WF/CC composite, and the Tcc peak at high temperature and Tm peak in the composite containing PMAVA were split into two peaks, showing that the effects of WF and CC on the crystal of PLA were uncorrelated, and the presence of PMAVA decreased the crystal integrity of PLA. The tensile test results showed that the tensile strength and modulus of the composite were increased with the addition of PMAVA, and the composite with 0.5 wt% of PMAVA owned the best tensile performance. The hydrolysis results showed that the use of low content of PMAVA in the composite was beneficial to improve its hydrolysis rate.

NIR-Photocontrolled Aqueous RAFT Polymerization with Polymerizable Water-Soluble Zinc Phthalocyanine as Photocatalyst

In order to give an answer for the challenges of long wavelength-photocontrolled radical polymerization in aqueous solutions and to address the shortcomings of conventional near-infrared (NIR) photocatalysts (PCs) that are difficult to subject to post-treatment, we designed and synthesized a series of β-tetra-substituted water-soluble zinc phthalocyanines (β-TS-Zns) as the NIR PCs for reversible addition-fragmentation chain transfer (RAFT) polymerization successfully under irradiation with NIR (λmax = 730 nm) light at room temperature. Importantly, the NIR PCs can also be designed as polymerizable monomers and covalently loaded on the polymer chains, which are endowed with permanent NIR photocatalysis of the resultant polymers. Moreover, the polymerization can not only be carried out in water but also in phosphate buffer saline (PBS) solution, yielding polymers with controlled molar mass and narrow dispersities (Đ = 1.03-1.25). Therefore, this NIR-photocontrolled aqueous RAFT polymerization system may provide a charming strategy for possible applications in tissue engineering biomaterial in situ benefiting from the high penetration ability of NIR light.

Preparation and performance of durable waterproof adhesive layer for steel bridge deck based on self-stratification effect

In view of the shortcomings of the existing steel bridge deck waterproof adhesive layer (WAL), such as poor durability, high construction cost and long construction period, a new preparation method of waterproof coating with self-stratification effect is proposed. In this paper, poly butyl acrylate-methyl methacrylate–styrene block copolymer with lower glass transition temperature was synthesized by free radical solution polymerization, and 5 kinds of self-stratification coatings were obtained by mixing it with epoxy resin at different mass ratios. The glass transition temperature, thermal stability and chemical composition of acrylic resin were characterized by DSC, TGA, and FT-IR. The self-stratification behavior of the coatings was confirmed by FT-IR, SEM, and water contact angle test. The basic performance and road performance of above self-stratifying waterproof coatings were tested according to specific standards. The results show that these coatings exhibit excellent heat resistance, low temperature flexibility and mechanical properties, namely, average tensile strength can reach 6 MPa, the elongation at break can reach 108 %. Furthermore, the coatings also present extraordinary pull-out strength of 9.51 MPa and excellent water impermeability. Moreover, the tensile strength and elongation at break of the self-stratifying waterproof coatings after UV aging test decreased by 7.3 % and 5.2 %, respectively, indicating that above coating have excellent durability. Therefore, the performance of the coating prepared in this paper fully meets the requirements of the road and bridge waterproof coating standards. The optimum mixing ratio of acrylic resin and epoxy resin is recommended as 3:7 based on their performance. Finally, self-stratifying mechanism of coatings was proposed based on the surface energy theory, which provides theoretical support for the design and preparation of the steel bridge deck WAL.