Graft Polymerization Technique Research Articles

Chemically Stable Styrenic Electrospun Membranes with Tailorable Surface Chemistry.

Membranes with tailorable surface chemistry have applications in a wide range of industries. Synthesizing membranes from poly(chloromethyl styrene) directly incorporates an alkyl halide surface-bound initiator which can be used to install functional groups via SN2 chemistry or graft polymerization techniques. In this work, poly(chloromethyl styrene) membranes were synthesized through electrospinning. After fabrication, membranes were crosslinked with a diamine, and the chemical resistance of the membranes was evaluated by exposure to 10 M nitric acid, ethanol, or tetrahydrofuran for 24 h. The resulting membranes had diameters on the order of 2-5 microns, porosities of >80%, and permeance on the order of 10,000 L/m2/h/bar. Crosslinking the membranes generally increased the chemical stability. The degree of crosslinking was approximated using elemental analysis for nitrogen and ranged from 0.5 to 0.9 N%. The poly(chloromethyl styrene) membrane with the highest degree of crosslinking did not dissolve in THF after 24 h and retained its high permeance after solvent exposure. The presented chemically resistant membranes can serve as a platform technology due to their versatile surface chemistry and can be used in membrane manufacturing techniques that require the membrane to be contacted with organic solvents or monomers. They can also serve as a platform for separations that are performed in strong acids.

Synthesis, Characterization, and Adsorptive Characteristics of Radiation-Grafted Glycidyl Methacrylate Bamboo Fiber Composites.

In the present study, a biosorbent was prepared through the radiation-induced graft polymerization (RIGP) technique by using a glycidyl methacrylate (GMA) monomer. Functionalized bamboo materials were used for grafting. The grafting percentage (G %) of GMA on bamboo fibers was assessed based on the optimization of the absorbed dose and concentration of the monomer. The chemical modification of the polymerized product into the sulfonated form of the grafted biopolymer was carried out by using sodium sulfite solution. The modification of the biopolymer at various stages was analyzed by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) techniques. By performing scanning electron microscopy (SEM), the morphological changes of the prepared biopolymer were analyzed. The temperature stability of the synthesized material was assessed by the thermogravimetric analysis (TGA) technique. The prepared sulfonated biosorbent was used in the batch adsorption study for the uptake of copper. We examined a variety of variables, including pH, adsorbent dosage, and time. The adsorption kinetics were studied using pseudo-first-order (PFO) and pseudo-second-order (PSO) models. Adsorption isotherms and thermodynamic parameters were also applied to study the adsorption capacity of the biosorbent. The maximum copper adsorption capacity was found to be 198 mg g-1 from the Langmuir isotherm. Copper adsorption followed PSO kinetics (R2 = 0.999). This inexpensive and eco-friendly biosorbent removed 96% of copper ions from the solution.

The enhancement of antibacterial and anti‐biofouling properties of chitosan/silver nanoparticles‐grafted composite polyamide membrane

AbstractThis study endeavors to augment the antibacterial and anti‐biofouling properties of thin‐film composite polyamide membranes by subjecting them to modification with antibacterial chitosan and silver nanoparticle materials through the UV‐induced graft polymerization technique. Various surface assessment methods were employed, and the efficiency of the membrane performance was demonstrated through the flux and the retention of the filtration process, which used calcium chloride as the foulant. Antibacterial, antifouling, and anti‐biofouling capabilities were assessed through several tests. The findings revealed that the chitosan/silver nanoparticles‐grafted membranes exhibited superior antibacterial and anti‐biofouling abilities with consistent flux and enhanced retention, underscoring the prospective implementation of this approach in filtration systems to curtail biofouling and bolster overall efficacy.

Microwave-assisted Synthesis of Acrylamide Grafted Polymeric Blend of Fenugreek Gum and its Characterization

Objective: In this study, fenugreek gum (isolated from fenugreek seed) was modified into a grafted form using a microwave-assisted method. Acrylamide was used as a monomer, and ceric ammonium nitrate (CAN), potassium persulfate (KPS), and ammonium persulfate (APS) were used as redox initiators. Methods: The experimental design (Taguchi OA) was used to optimize the synthesis of the grafted copolymer of fenugreek gum. In this model, seven independent variables were selected on the basis of their preliminary study. These were monomer concentration (X1), gum concentration (X2), initiator concentration (X3), irradiation power (X4), speed (X5), time (X6), temperature (X7), and three response variables as % yield (Y1), % grafting (Y2), and % grafting efficiency (Y3) were identified. The optimized copolymers of grafted gum were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), NMR studies, surface morphology and swelling index. Results: The yield of fenugreek gum after extraction was found to be 55.99±0.015% w/w. The percentage grafting of 50.20±4.0, along with grafting efficiency of 83.7±0.1, was obtained with the selected concentration of acrylamide as 15 mg, grafted gum as 0.25 mg, and ammonium persulfate as 0.2 mg after 60 sec. of irradiation time. Conclusion: In the present study, the graft copolymers of fenugreek gum were synthesized. After optimization of the grafting batch, the design (Taguchi OA) was combined with a desirability function. The results underline the importance of graft polymerization techniques for modifying the properties of a polymer.

Strategies toward the Synthesis of Advanced Functional Sorbent Performance for Uranium Uptake from Seawater

A polymer fiber-based adsorbent (AF1) composed of acrylonitrile and itaconic acid functional groups was synthesized by a radiation-induced graft polymerization technique onto hollow-gear shaped polyethylene (PE) fibers. Investigation of the optimum reaction parameters for the conversion of grafted cyano moieties into amidoxime groups was conducted by the reaction with hydroxylamine at different temperatures and periods in a variety of aqueous and organic solvents. The 13C CP/MAS spectra of amidoximated AF1 adsorbent fibers from water–methanol and dimethyl sulfoxide (DMSO) revealed that both the cyclic imide dioxime and open-chain amidoxime were formed through the reaction. The conversion from amidoxime to imide dioxime was found to occur slowly and gradually with the increasing reaction time. The quicker diffusion of DMSO as compared to that of water–methanol, in the grafted trunk PE fiber, resulted in faster kinetics of the amidoximation reaction. The uranium adsorption capacity of the amidoximated AF1 samples was determined after (i) 24 h contact with sodium-based brine spiked with uranium and (ii) 56 days of exposure to filtered seawater (Sequim Bay, WA, USA) in flow-through columns. The uranium extraction performance of the adsorbents after exposure to filtered seawater was consistent with the laboratory screening results, and the amidoximated AF1 samples (in DMSO at 70 °C for 3 h) exhibited the highest 56 day uranium adsorption capacity (5.04 ± 0.15 g U/kg-ads) with faster adsorption kinetics compared to the pristine AF1 adsorbents.

Self-assembling of NCQDs-TiO2 nanocomposite on poly(acrylic acid)-grafted polyethersulfone membrane for photocatalytic removal and membrane filtration

Considering the tedious post-reaction recovery of nano-sized phototcatalysts and the critical fouling problem faced in membrane separation, incorporation of photocatalyst with polymeric membrane has been developed to alleviate these issues. In this study, polyethersulfone (PES) membrane was synthesized by phase inversion method and poly-acrylic acid (PAA) was later grafted onto the PES surface via UV-induced graft polymerization technique. The PAA film has introduced –COOH functional groups for the surface immobilization of green nitrogen-doped carbon quantum dots-titanium dioxide (NCQDs-TiO2) photocatalyst via a self-assembly approach. The PAA-modified supporting layer and the NCQDs-TiO2 functional layer were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) and Fourier transform infrared spectroscopy (FTIR). The characterization results evidenced that PAA chains were successfully polymerized on PES support while the nanocomposite was firmly deposited on the PAA-grafted membrane. The novel NCQDs-TiO2/PAA/PES composite membrane demonstrated excellent photocatalytic capability, wherein 94.41% of methylene blue (MB) was removed under 1 h of visible-light irradiation. The antifouling property of the modified membrane was proven by the rapid flux stabilization and the high flux recovery ratio of 83.92%. The current research work proposed the synergistic use of visible-light responsive photocatalytic membrane in the degradation and filtration of wastewater, which is more energy-efficient and could reduce secondary pollution.

Preparation and optimization of thorium selective ion imprinted nonwoven fabric grafted with poly(2-dimethylaminoethyl methacrylate) by electron beam irradiation technique

2-dimethylaminoethyl methacrylate (DMAEMA) was grafted onto PP/PE non-woven fabrics (NWF) using pre-radiation graft polymerization technique and subsequent mutual radiation crosslinking with divinylbenzene (DVB). The ion-imprinted polymer (IIP) was synthesized by DVB crosslinking with DMAEMA and thorium complex through radiation. Non-imprinted polymer (NIP) was prepared with the same conditions but utilizing pure DMAEMA instead of DMAEMA-Thorium complex. The NWF, DMAEMA-grafted-NWF, IIP and NIP were characterized with Field Emission Scanning Electron Microscopy (FESEM), Fourier Transformed Infrared Spectroscopy (ATR-FTIR), Thermogravimetric Analyzer (TGA), X-ray photoelectron spectroscopy (XPS), and X-ray Diffraction (XRD). The grafting process parameters were optimized prior to radiation crosslinking with DVB. The effects of DMAEMA concentration and reaction temperature as a function of different irradiation doses were investigated in order to attain optimal grafting conditions. The effects of DVB concentration, process temperature and radiation dosage on the degree of crosslinking were examined. In addition, the effects of crosslinking percentage, initial thorium concentration and concentration of imprinted thorium to the selectivity of IIP and NIP were also determined. The thorium selectivity of both IIP and NIP was measured using batch mixed ions system by inductively coupled plasma mass spectrometry (ICP-MS) analysis. Instead of simultaneous grafting and crosslinking process in bulk along with imprint template, this current study conciliates all grafting, imprint template and crosslinking process independently. Thus, the originality of the research is attributed to individuality grafting and crosslinking technique using ion beam irradiation to obtain IIP of high thorium selectivity without compromising the chemical and physical properties of the adsorbent.

Grafting yield determination of glycidyl methacrylate vapor on radiated kenaf fiber via FTIR spectroscopy

In this study, glycidyl methacrylate (GMA) was grafted onto kenaf fiber using radiation-induced graft polymerization technique in vapor phase. The pre-irradiation of kenaf fiber was carried out at different doses from electron beam accelerator at various absorbed radiation doses (10 to 100 kGy). The grafting process was carried out in a vapor-phase graft polymerization reactor operated at temperature of 40 °C. The grafted chains were verified with FT-IR spectroscopy analysis. The percentage of grafting, Pg (%) of the grafted kenaf fiber was calculated based on quantitative Fourier transform infra-red spectroscopy (FTIR) analysis. Functional group present onto the kenaf fiber backbone after grafting was used to quantify the unknown amount of GMA grafted to the kenaf fiber and to calculate the Pg (%). Characteristic peak of 1725 cm−1 corresponding to the carbonyl group of GMA was chosen for calibration purpose in order to derive a linear regression plot of peak area versus the weight per volume percent of GMA (w/v%). The correlation coefficient for the calibration line is 0.967, which indicates that the correlation between absorbance and concentration is good. It was observed that grafting of vapor GMA onto pre-irradiated kenaf fiber reach the maximum yield of 191.89% with the absorbed radiation dose of 50 kGy.

Characterization and sludge dewaterability evaluation of a chitosan‐based flocculant CMCTS‐g‐CPAM

AbstractIn this work, a new cationic flocculant, CMCTS‐g‐CPAM was synthesized by acrylamide (AM), methacryloyloxyethyltrimethylammonium chloride (DMC) and carboxymethyl chitosan (CMCTS) through UV initiated graft polymerization techniques. The structure of CMCTS‐g‐CPAM was analysed by infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (1H NMR) and X‐ray diffraction (XRD) techniques which indicates that AM and DMC are grafted successfully onto CMCTS to obtain CMCTS‐g‐CPAM. The potential of CMCTS‐g‐CPAM for the sludge dewatering was investigated. The effects of cationic degree, intrinsic viscosity, dosage and pH on the sludge dewatering performance were studied. The results indicate that the optimal dewatering performance with minimum supernatant turbidity of 5.40 NTU, the moisture content of the filter cake of 79.28% and the specific resistance of the sludge of 1.96 × 1013 m/kg was obtained at 30 mg/L CMCTS‐g‐CPAM at pH 9–10. Finally, from the microscopic and electron micrographs investigation, it was confirmed that the particle size of the CMCTS‐g‐CPAM treated sludge was significantly large to enhance hydrophobicity and improve dewatering performance.

Flow-Based Immunosensing Using the Pore Channel of a Porous Membrane As a Reaction Space.

This Letter describes a new rapid and sensitive immunosensing device using the pore space of a porous membrane as the reaction space. A track-etched membrane with uniform cylindrical pores is used as the base substrate of this device. The capture antibodies are covalently and densely immobilized inside the membrane pores by the uniform introduction of poly(acrylic acid) (PAAc) via the plasma graft polymerization technique, followed by the active ester method. This membrane shows excellent antibody retention by covalent binding. The detection test was carried out via a sandwich-type assay, and all reaction steps from the antigen-antibody reaction to the enzyme reaction were conducted by permeating each solution into the pores. The detection test showed a signal comparable to that of the conventional enzyme-linked immunosorbent assay, although the detection time required in the test was shortened to 35 min. The reason for achieving both high sensitivity and short detection time is that the antibody accumulated pore space with high selectivity and promoted contact between the reactants by solution permeation. This report is expected to aid the design of systems for membrane-based devices, which currently have problems associated with sensitivity, rapidity, selectivity, or amount of sample. We further expect that this system could be applied to various diagnostic areas, including point-of-care testing.

Modeling a pH-sensitive Zein-co-acrylic acid hybrid hydrogels loaded 5-fluorouracil and rutin for enhanced anticancer efficacy by oral delivery.

The combination of natural and synthetic polymeric materials grafted hydrogels offer great potential as oral therapeutic systems because of its intrinsic biocompatibility, biodegradability, protect labile drugs from metabolism and controlled release properties. Hence, in the present study, we aimed to prepare and optimize oral delivered pH-responsive Zein-co-acrylic acid hydrogels incorporated with 5-fluorouracil (5-Fu) and rutin (Ru) for effective anticancer activity with less toxicity. In this study, graft polymerization technique is adopted to formulate hydrogels with various ratios of Zein, acrylic acid, N, N-methylene bisacrylamide, and ammonium persulphate as an initiator. The optimized formulation was identified based on the cross-linking, chemical interactions, intrinsic viscosity (η), dynamic swelling (Q) at pH 1.2, diffusion coefficient (D), sol-gel fraction (%), and porosity (%). The selected optimized formulation has shown significant improvement in drugs loading and encapsulation efficiency, releasing at pH 1.2 and pH 7.4. Drug release kinetics studies confirmed the controlled release properties of hydrogels. Hydrogels were porous and the drug loading of 5-Fu and Ru was found to be 12.13% and 10.86%, respectively, whereas encapsulation efficiency of 5-Fu and Ru was 89.35% and 81.47%, respectively. Furthermore, form the in vitro cytotoxic screening, it was found that 52.5 µgmL-1 5-Fu and Ru-loaded hydrogel impacted 50% of cell death at 24h, there by significantly arresting the proliferation of MDA-MB-231 and MCF-7 breast cancer cell lines. Altogether, the optimized pH-responsive hydrogels make them favorable carrier for anticancer drugs for oral delivery.

Improvement in Molecular-Level Adhesive Strength of PTFE Film Treated by Atmospheric Plasma Combined Processing

Atmospheric pressure plasma graft polymerization-treated fluorocarbon plastics are bonded with a metal, to evaluate adhesiveness. In this research, the atmospheric nonthermal plasma graft polymerization technique is used in treating the surface of polytetrafluoroethylene (PTFE) in a dry process, capable of reducing environmental loading. The treated PTFE is joined with the stainless steel plate to perform a peeling test. We examine the peeling strength and the best condition for practical application using peeling strength as an optimization variable. A concrete numerical target is 2 N/mm, which is the standard adhesive strength applicable for industry uses. To conduct the graft polymerization, we use a monomer such as acrylic acid (CH2 = CHCOOH) and target material such as PTFE. Peeling strength is maximized (averaged value of 1.56 N/mm, largest value of 2.0 N/mm) when the temperature of the acrylic acid is 60 °C and the Ar main flow rate is 40 L/min. Influence of plasma torch cover on peeling strength and entrained flow near the torch are investigated to realize the stronger adhesion, and better shape of the cover is determined. Furthermore, by analyzing X-ray photoelectron spectroscopy and scanning electron microscope images, we evaluate the atmospheric pressure plasma graft polymerization process from a different perspective and search for optimal operating conditions of the processing method.

Basicity‐dependent properties of anion conducting membranes consisting of iminium cations for alkaline fuel cells

ABSTRACTTo design novel anion‐conducting polymer electrolyte membranes (AEMs), this paper proposes a basicity index (BI) that is defined by the ion‐exchange ratios of AEMs from the OH− to Cl− forms in a neutral aqueous solution as a parameter for Arrhenius basicity (dissociation constant). Using a radiation‐induced graft polymerization technique, three iminium cations are introduced into fluorinated polymer films. The BI of the iminium‐containing AEMs is less than that of a conventional ammonium‐type AEM. The conductivity and water uptake correlate positively with the BI, whereas the thermal and chemical stabilities correlate negatively with the BI. The dependence on the BI stems from the stabilization of the iminium hydroxide in proportion to the basicity of the original diaza‐compounds, resulting in a decrease in conductivity and water uptake with keeping higher thermal and chemical stabilities. Notably, ion conductivity is sufficient and water uptake is less in AEMs with a medium BI. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 503–510

A Microwave- irradiated Novel Superabsorbent Polymer Hydrogel (Guar gum-g- PAA): Synthesis, characterization and property studies

The main aim of the present study was to synthesize Guar gum grafted poly acrylic acid (Gg-g-PAA) superabsorbent polymer (SAP) hydrogel via free radical emulsifier-free emulsion graft polymerization technique using microwave irradiation. The so prepared superabsorbent polymer hydrogel was characterized by Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM). The properties like swelling ability and biodegradability were also studied which has a profound influence in agriculture, biomedicine, pharmaceutics, etc. The SAP may potentially be used for the fast release of medicine in high pH environment. It also may have found its application and sustainability in the removal of heavy metal ions from the waste water through adsorption leading to water remediation.

Immobilization of Glucose Dehydrogenase on Epoxy Group-Modified MgO-Templated Porous Carbon Electrode for Improvement of Biofuel Cell Stability

Enzymatic glucose/O2 biofuel cells (BFCs) are energy conversion systems in which enzymes oxidize glucose at a bioanode and reduce oxygen at a biocathode. These enzymes are highly safe toward humans, and highly selective for substrates, without leaving toxic residues at room temperature and neutral pH conditions. There are many recent studies on self-powered biosensing systems based on BFCs. We have reported that the output power is dramatically improved by using MgO-templated porous carbon (MgOC) for electrodes of biofuel cells [1-2]. MgOC has suitable mesopores for entrapping an enzyme whose redox center can approach the carbon surface with high probability. In addition, the long-term stability may be improved because the ellusion of the enzyme was suppressed by entrapping the enzyme in the mesopore. In this study, we newly performed chemical immobilization of glucose dehydrogenase (GDH) on the MgOC surface to improve the long-term stability further. A MgOC poweder having an average pore diameter of 100 nm was purchased from by Toyo Carbon Co. Ltd. The epoxy group-modified MgOC was synthesized by graft polymerization technique. The epoxy group-modified MgOC was coated on a glassy carbon electrode, and then 1,2-naphthoquinone(1,2-NQ) was modified as a mediator and glucose dehydrogenase (FAD-GDH) was modified as an enzyme to be prepared an enzyme electrode. Cyclic voltammetry and chronoamperometry of the enzyme electrode were measured in a 3-electrode system in 1.0 M phosphate buffer solution (PBS) containing 100 mM glucose. Stability of the enzyme electrode was evaluated by performing cyclic voltammetry in multiple cycle measurement. Figure 1 shows the cyclic voltammogram of enzyme electrode. Catalytic oxidation current was observed at a nobler potential than -0.1 V. Also, the maximum current value in the 1st cycle was 11.2 mA cm-2. The peak current value of the present enzyme electrode was almost the same compared with that of an enzyme electrode in which epoxy group-unmodified MgOC was used as the electrode material. The results indicated that the enzymatic activity of FAD-GDH was not changed by the chemical immobilization. Figure 2 shows the relation between the number of cycles and normalized current density at 0.3 V. When the MgOC was modified by epoxy group, the current value of 90% was retained after 25 cycles, whereas it was 52% in the case of unmodified MgOC. From the above results, Elution of FAD-GDH could be suppressed by using epoxy group-modified MgOC because the amino group of the enzyme shell and the epoxy group on the carbon surface are bonded successfully.

Heparin molecularly imprinted polymer thin flm on gold electrode by plasma-induced graft polymerization for label-free biosensor

Heparin, a highly sulfated glycosaminoglycan, is an important biomaterial having biological and therapeutic functionalities such as anticoagulation, regeneration, and protein stabilization. This study addresses a label-free quartz crystal microbalance (QCM) biosensor for heparin detection based on a macromolecularly imprinted polymer (MIP) as an artificial recognition element. We demonstrate the novel strategy for MIP in the form of thin film on a gold (Au) electrode with the plasma-induced graft polymerization (PIP) technique. The procedure of PIP is as follows: (i) Hexamethyldisiloxane plasma-polymerized thin film (PPF) as a pre-coating scaffold of active species for PIP (post-polymerization) is deposited on an Au electrode. (ii) The PPF/Au electrode is soaked in an water solution containing heparin (template), (2-(methacryloxy)-ethyl)trimethylammonium chloride acrylamide (functional monomer), acrylamide, and N,N-methylenebisacrylamide (crosslinker). Double bonds of monomer and crosslinker attacked by residually active species in pre-coating PPF cause radical chain reaction. Consequently, a growing polymer network of 20 nm thickness of PIP-MIP thin film is formed and grafted on the PPF/Au surface. (iii) The PIP-MIP/PPF/Au is washed by sodium chloride solution so as to remove the template. Non-imprinted polymer (NIP) is carried out like the same procedure without a template. The AFM, XPS, and QCM measurements show that the PIP process facilitates macromolecularly surface imprinting of template heparin where the template is easily removed and is rapidly rebound to PIP-MIP without a diffusional barrier. The heparin-PIP-MIP specifically binds to heparin compared with heparin analog chondroitin sulfate C (selective factor: 4.0) and a detectable range of heparin in the presence of CS (0.1 wt%) was 0.001-0.1 wt%. The PIP-NIP does not show selectivity between them. The evaluated binding kinetics are association (ka = 350 ± 100 M−1 s−1), dissociation (kd = (5.0 ± 2.0) × 10−4 s−1), and binding (KD = 1.3 ± 0.6 μM) constants, demonstrating that the PIP-MIP as a synthetic antibody can be applied to analytical chemistry.

Development of a water purifier for radioactive cesium removal from contaminated natural water by radiation-induced graft polymerization

Six years after the Fukushima-nuclear accident, the dissolved radioactive cesium (Cs) is now hardly detected in environmental natural waters. These natural waters are directly used as source of drinking and domestic waters in disaster-stricken areas in Fukushima. However, the possibility that some radioactive Cs adsorbed on soil or leaves will contaminate these natural waters during heavy rains or typhoon is always present. In order for the returning residents to live with peace of mind, it is important to demonstrate the safety of the domestic waters that they will use for their daily life. For this purpose, we have synthesized a material for selective removal of radioactive Cs by introducing ammonium 12-molybdophosphate (AMP) onto polyethylene nonwoven fabric through radiation-induced emulsion graft polymerization technique. Water purifiers filled with the grafted Cs adsorbent were installed in selected houses in Fukushima. The capability of the grafted adsorbent to remove Cs from domestic waters was evaluated for a whole year. The results showed that the tap water filtered through the developed water purifier contained no radioactive Cs, signifying the very effective adsorption performance of the developed grafted adsorbent. From several demonstrations, we have commercialized the water purifier named “KranCsair®”.Furthermore, we have also developed a method for the mass production of the grafted nonwoven fabric. Using a 30L grafting reactor, it was possible to produce the grafted nonwoven fabric with a suitable range of degree of grafting. When an irradiated roll of nonwoven trunk fabric with a length of 10m and a width of 30cm was set in the reactor filled with glycidyl methacrylate (GMA), AMP, Tween 80 monomer emulsion solution at 40°C for 1h, the difference of Dgs in the length and the width on roll of fabrics was negligible.

Preparation of cationic functional polymer poly(Acryloxyethyltrimethyl ammonium chloride)/SiO2 and its adsorption characteristics for heparin

Ion-exchange is a widely used purification technology in the heparin manufacturing process. To improve the rate and efficiency, the cationic monomer Acryloxyethyltrimethyl ammonium chloride (DAC) was grafted on silica gel particles by using a surface-initiated graft-polymerization technique, and a novel adsorption polymer of PDAC/SiO2 was prepared. The adsorption experiments of PDAC/SiO2 for heparin show that there are strong electrostatic interactions between heparin with a high density of negative charges and PDAC/SiO2 that exists in many quaternary ammonium cations. Comparing the adsorption kinetics of PDAC/SiO2 with D201 anionic strong alkali exchange resin, PDAC/SiO2 shows higher adsorption capacity and faster adsorption rate. The pH and temperature of solutions have a great influence on the adsorption amount, and there is a maximum adsorption capacity of 121mg/g when pH=7 at 25 °C. The adsorption of PDAC/SiO2 for heparin is an exothermic process and driven by entropy.

In vitro anticoagulant activity of polyanionic graft chains modified poly(vinyl alcohol) particles

Poly(acrylic acid), poly(sodium styrenesulfonate), and poly(acrylic acid-co-sodium styrenesulfonate) chains were immobilized onto poly(vinyl alcohol) (PVA) particles via a facile γ-ray simultaneous irradiation induced graft polymerization technique, which were confirmed by the attenuated total reflection Fourier transform infrared spectroscopy and the high swelling ratios of modified PVA particles. The effects of absorbed dose, dose rate, Cu2+ concentration and monomer concentration on the degree of grafting (DG) of PVA particles were investigated to find out a feasible process for preparing polyanionic chains graft-modified PVA particles. The clotting time results illustrated that both PVA-g-PAA and PVA-g-PSSS particles presented excellent anticoagulant activity, and the activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) were effectively prolonged with the increase of DGAA and DGSSS, respectively. Furthermore, the anticoagulant activity of PVA-g-PSSS samples was more efficient than that of PVA-g-PAA samples. However, the anticoagulant effect of PVA-g-P(AA-co-SSS) samples was different from that of PVA-g-PAA and PVA-g-PSSS samples, and was similar to that of heparin, mainly elongating the APTT and TT. This might be due to both of them containing the same negative-charged groups. Additionally, the grafted PVA particles were all non-hemolytic, showing good blood compatibility.

Effect of Cross-Linker Concentration on the Synthesis and Swelling Behaviour of Superabsorbent Polymers (SAP) Using Graft Polymerization Techniques

The graft polymerization of acrylic acid by varying the amount of cross-linker in ranging of 0.001 g to 0.05 g was investigated. The effect of cross-linker in synthesized superabsorbent polymers (SAP) was identified in terms of water absorbency responses by keeping the values of monomer and initiator. The implementation of SAP in agriculture could develop plant growth, enhancing water retention capacity in soils which can reducing dewatering system and improved the efficiency of soil condition so higher yield of product can be obtained particularly in arid regions. The SAPs were synthesized by graft polymerization using acrylic acid (AA) as monomer, N,N’-methylene bisacrylamide (MBA) as cross-linker and ammonium persulfate (APS) as initiator. The optimum water absorbency of synthesize SAP was defined using tea-bag method in deionize water. The structures of synthesize SAP was characterized by Fourier Transform Infrared Spectroscopy (FTIR) and morphologies of synthesize SAP was examined by Scanning Electron Microscope (SEM) testing. From the result, it was obvious showed that water absorbency will decreased as the increased of concentration of cross-linker which is MBA in synthesize SAP. The best value content of MBA was 0.01 g which achieved the highest water absorbency response which is 170 g water/g sample. In conclusion, SAP has hydrophilic structure of which renders them capable for holding a large amount of water which can help to retain nutrients and absorb water in soil with various applications for plant growth and soil condition which will be useful especially in agriculture field.