Grafting Of Methyl Methacrylate Research Articles

Surface modification of polytetrafluoroethylene (PTFE) fibers through methyl methacrylate (MMA) polymerization for self-lubricating composites

PTFE fibers exhibit strong inertia and possess restricted interfacial compatibility with resin, thereby constraining the application of PTFE self-lubricating composites. To address this issue, PTFE-g-MMA fibers were synthesized by grafting MMA onto the surface of PTFE fibers using high-energy irradiation and chemical grafting techniques, resulting in the enhancement of the tribological properties (the friction coefficient has been reduced by approximately 42.2% and the wear rate has been reduced by about 87.9%) and mechanical properties (the interlaminar shear strength (ILSS) experienced a substantial increase of approximately 45.8%) of the composites. The influence of grafting modification on the formation of PTFE transfer films and the effect of modification time on the tribological properties of composites were investigated systematically. The results indicated that graft modification disrupted the C–F bond of PTFE and promoted the formation of metal-chelated carboxylates, facilitating the formation of PTFE transfer films on the counter surface. This research could provide a general and feasible strategy for large-scale modification of PTFE fibers with exceptional comprehensive properties.

Investigation of Thermal Decomposition and Thermal Oxidative Degradation of a Composite of Cellulose Nanofibers and Deproteinized Natural Rubber Grafted Methyl Methacrylate

Natural rubber (NR) is a polymer that has many applications in daily life. However, the traditional rubber industry relies heavily on petroleum-based materials, causing environmental pollution problems. Therefore, to reduce environmental challenges, products created from NR are combined with non-toxic chemicals and natural fillers such as cellulose nanofibers (CNF). This study presents the effect of CNF on the thermal properties of novel composites made from CNF and deproteinized natural rubber grafted methyl methacrylate (DPNR-g-MMA) under air and nitrogen atmosphere. Graft copolymerization of MMA onto DPNR to produce DPNR-g-PMMA was performed in the latex phase. The CNF/DPNR-g-PMMA composite was created by dispersing CNF in DPNR-g-PMMA at ratios of 0.5%, 1%, and 1.5% using ultrasonic waves. DPNR-g-PMMA was employed as the composite's matrix and CNF served as its reinforcing phase. Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance spectroscopy (1H NMR) were used to confirm the success of the graft copolymerization. The thermal properties of materials were studied by Thermalgravimetric analysis (TGA) and Differential scanning calorimetry (DSC), in which the thermal stability of composites was examined via TGA under air and nitrogen atmosphere. The obtained data illustrate that, in comparison to DPNR and DPNR-g-PMMA, the decomposition temperature of all CNF/DPNR-g-PMMA composites, especially at CNF ratio of 1%. After blending CNF to DPNR-g-PMMA, the decomposition temperatures of CNF/DPNR-g-PMMA 1% increased by nearly 2 °C in nitrogen atmosphere and by 5.27 °C in air atmosphere. These results prove that the CNF is a key role in the thermal stability of DPNR-g-PMMA.

Antimicrobial Biomaterials via Simultaneous Grafting of Methyl Methacrylate and N‐Vinyl Pyrrolidone onto Chitosan

AbstractChitosan is an antimicrobial biopolymer with significant potential for manufacturing biodegradable and biocompatible materials through further functionalization. These materials could be highly suitable for biomedical applications. In this study, in order to obtain better properties such as antimicrobial activity and adjustable hydrophilicity for biopolymer‐based applications, N‐vinylpyrrolidone (VP) and methylmethacrylate (MMA) were simultaneously grafted onto chitosan by a ceric‐initiated emulsion polymerization method. The chemical structure, thermal, morphological, and antimicrobial properties of the resulting materials were investigated. The results revealed that PMMA and PVP pendant groups were grafted onto the chitosan main chain. According to SEM measurements, the obtained materials had spherical shapes with diameters ranging from 250 to 950 nm for the components. In vitro antibacterial activity against both Gram‐positive and Gram‐negative bacteria was significantly improved in the obtained materials compared to pristine chitosan.

Electron Beam-Initiated Grafting of Methyl Methacrylate on Silicon Nanowires: Investigating Optical and Structural Properties

Silicon nanowire (SiNW) is a one-dimensional nanostructured material that had been widely studied due to its potential applications in various fields. Combination of polymers and nanostructured materials offers great potential for enhanced material with many possible applications. The investigation focuses on how this grafting process influences the optical properties of SiNWs, aiming to uncover potential applications for these hybrid materials. This paper comprehensively presents the methodology and characterization of these SiNWs-MMA hybrid materials, exploring their potential applications. The experimental process begins with the preparation of six SiNWs using RF magnetron sputtering, involving the deposition of an Au catalyst and subsequent growth of SiNWs. The radiation-induced grafting involves exposing SiNWs to electron beams and subsequently grafting MMA onto the surface. The outcomes reveal that the grafting percentage of MMA onto SiNWs increases with higher radiation doses, leading to a polymer layer covering the SiNWs. This grafting is confirmed through Fourier-transform infrared (FTIR) spectroscopy, which shows characteristic peaks of MMA on the surface. X-ray diffraction (XRD) analysis demonstrates changes in crystallite size, microstrain, and dislocation density upon grafting, which are attributed to stress relief and the effect of polymer on SiNWs’ lattice. Field emission scanning electron microscopy (FESEM) images exhibit the increasing MMA layer on SiNWs as the grafting percentage increases. UV-visible spectroscopy shows that the introduction of MMA increases the optical band gap of SiNWs, attributed to changes in surface roughness due to the carbon from MMA. This study introduces a novel method of hybridizing SiNWs with MMA through radiation-induced grafting. The detailed characterization of the resulting SiNWs-MMA hybrid materials sheds light on their structural and optical properties. These findings hold the promise of innovative applications in various technological fields, further advancing nanotechnology.

Thermal stability and optical properties of radiation-induced grafting of methyl methacrylate onto low-density polyethylene in a solvent system containing pyridine

Abstract In this study, the grafting of methyl methacrylate (MMA) in a solvent system containing nitrogen of pyridine onto LDPE films was performed using the post-irradiation technique in nitrogen at different gamma doses. The DG% obtained in MMA grafting was 71.0% at 10 kGy of γ dose was increased to 90% in (MMA/Py) (80/20 v/v%) system, indicating the existence of Py enhancement in the grafting % of MMA. The addition of pyridine (Py) into MMA matrix increases the molecular weight of the matrix due to the plasticizing effect of Py on the system. Morphological and structural changes in optical properties and thermogravimetric analysis were performed for the films. According to Fourier transform infrared data, a reaction may be placed between Py and MMA molecules. Furthermore, the effect of Py molecules on the optical properties of LDPE films is studied. The optical transition upon the grafting process increased, indicating the movement of the electrons due to intramolecular hydrogen bonds between MMA and Py molecules. The Urbach energy and the optical band gab, E g, were investigated and found to depend mainly on the grafting degree. The results obtained from E g calculations recommended using an irradiation dose of 15 kGy to get LDPE-g-MMA/Py films with suitable optical properties.

Quantitative trap analysis of grafting-modified polypropylene based on thermally stimulated depolarization current

• MMA-grafted PP is prepared with enhanced DC resistivity and more deep traps. • Trap characteristics of MMA-grafted PP based on TSDC is quantitatively analyzed. • MMA deepens the inherent PP trap depth and introduces a new deep trap of 1.8 eV. In this paper, the thermally stimulated depolarization current (TSDC) spectrum of methyl methacrylate (MMA)-grafted polypropylene is quantitatively analyzed by our TSDC peak separating algorithm. The separated trap peaks and extracted trap parameters are verified to be effective and credible by the experimental peak-separating method based on thermo-cleaning. The trap analysis on pristine and MMA-grafted polypropylene is carried out and indicates that grafting MMA can introduce a new high-depth trap peak at about 1.8 eV, meanwhile the intrinsic trap of polypropylene is deepened. This work would provide an opportunity to advance the understanding of trap characteristics in grafting-modified polypropylene.

Grafting of Methyl Methacrylate onto Gelatin Initiated by Tri-Butylborane-2,5-Di-Tert-Butyl-p-Benzoquinone System.

Graft gelatin and poly(methyl methacrylate) copolymers were synthesized in the presence of the tributylborane—2,5-di-tert-butyl-p-benzoquinone (2,5-DTBQ) system. The molecular weight parameters and morphology of the polymer indicate that it has a cross-linked structure. Obtained data confirm the simultaneous formation of a copolymer in two ways: “grafting from” and “grafting to”. It leads to the cross-linked structure of a copolymer. This structure was not obtained for copolymers synthesized in the presence of other initiating systems: azobisisobutyronitrile; tributylborane; azobisisobutyronitrile and tributylborane; azobisisobutyronitrile, tributylborane, and 2,5-di-tert-butyl-p-benzoquinone. In these cases, the possibility of the formation of the copolymer, simultaneously in two ways, was excluded. Graft gelatin and poly(methyl methacrylate) copolymers synthesized in the presence of the tributylborane—2,5-di-tert-butyl-p-benzoquinone system are promising in terms of their use in scaffold technologies due to the three-dimensional mesh structure, providing a high regenerative potential of materials.

Enhanced thermal stability and UV resistance of polyamide 6 filament fabric via in-situ grafting with methyl methacrylate

Functionalized polyamide 6 (PA 6) filament fabric with excellent thermal stability and UV resistance was copolymerized with methyl methacrylate (MMA) via in-situ grafting initiated by immobilized ascorbic acid and hydrogen peroxide. Grafting modification process was determined at 30 % of H2O2, at 70 °C for 60 min of duration, and the grafting degree could be tuned by adjusting the amount of MMA. Microscopic investigations confirmed the granular MMA was immobilized on the surface of PA 6 fibers. A strong peak at 1729 cm−1, assigning to CO stretching of ester bond of MMA, demonstrated MMA was successful grafted. The decomposition temperature of grafted PA 6 occurring at 444.6 °C, was 40 °C higher than that of pristine PA 6 (403.4 °C). Additionally, the introduction of MMA also improved the UV resistance of PA, more than 80 % decrease in transmittance of UVA band and UVB band with only 0.34 % grafting degree. Therefore, it can be concluded that in-situ grafting of MMA can endow PA 6 with excellent thermal stability and UV resistance. We believe that in-situ grafting of MMA would have important guiding significance for the fabrication of PA 6 based textiles with excellent thermal stability and UV resistance.

Modification of High‐Density Polyethylene through the Grafting of Methyl Methacrylate Using RAFT Technique and Preparation of Its Polymer/Clay Nanocomposites**

AbstractA well‐defined method for discovering an easy and effective strategy through graft copolymer derived from poly (methylmethacrylate) (PMMA) as a monomer, high‐density polyethylene (HDPE) and its organoclay nanocomposite with physicochemical and mechanical properties was successfully prepared by reversible addition‐fragmentation transfer (RAFT) polymerization, and factors organoclay (Cloisite® 20 A) on the terminal features of the obtained graft copolymer were investigated. First, maleic anhydride (MA) was grafted onto HDPE directed by, the inauguration of an anhydride chain with ethanolamine to develop a hydroxylated high‐density polyethylene (HDPE‐OH). After that, the hydroxyl masses were esterified by using RAFT agent, 4‐cyano‐4‐[(phenyl carbon thionyl) sulfanyl valeric acid to obtain HDPE‐CTA macroinitiator. Then, the MMA monomer was grafted onto HDPE via the RAFT method to obtain the HDPE‐g‐PMMA graft copolymer. In the end, HDPE‐g‐PMMA/clay nanocomposite by a solution intercalation method was synthesized. The structures of the, copolymer and nanocomposite were studied by Fourier transform infrared spectroscopy, X‐ray diffraction, and Transmission electron microscopy (TEM) techniques. It explores for the synthesis of HDPE‐g‐PMMA/clay nanocomposites, disclosed a foliated structure. Based on the thermic behavior, synthesized HDPE‐g‐PMMA/clay nanocomposites can display the above thermic solidity with just some extent (5) of organoclay.

Controlled preparation of grafted starch modified with Ni nanoparticles for biodegradable polymer nanocomposites and its application in food packaging.

Grafting of starch with methyl methacrylate was carried out using a free radical mechanism. Free radicals were generated by the thermal disintegration of potassium persulphate at the temperature of 60°C. A variety of experimental methods were investigated to check the effect of different parameters such as (temperature, amount of starch, quantity of monomer) for efficient grafting. The optimum temperature found for good grafting was 60°C. The initial amount of starch was taken as 0.75 g. Keeping the amount of starch constant, the quantity of monomer was reduced gradually from 10 to 2ml in portions of 5 and 3ml. The controlled biodegradability of the grafted product was obtained by using a 3ml monomer in 0.75 g starch. This grafted polymer showed 31.45% biodegradability in 60 days. The nanocomposite of starch grafted methyl methacrylate was prepared by incorporating 0.02 g Ni nanoparticles in the reaction flask 15 min before the completion of reaction time. The starch grafted polymer and nanocomposite of this were fully characterized by SEM, FTIR, TGA, and DSC techniques. The soil burial method was applied to estimate the biodegradability of samples. The polymer containing Ni nanoparticles was less biodegradable than without nanoparticles. Such polymers can be efficiently used as packaging material for food items. RESEARCH HIGHLIGHTS: Through a free radical method, methyl methacrylate was grafted onto the backbone of starch in this study. During the process, nickel nanoparticles were added to achieve the nickel nanocomposite of the starch grafted polymer. The breakdown of starch grafted polymer after 60 days in a soil burial experiment was 31.45%, whereas the degradation of nanocomposites was 20.07%. Our synthesized nanocomposite polymers can be effectively employed as packaging material for food items.

Preparation of high-performance PVDF mixed matrix membranes incorporated with PVDF-g-PMMA copolymer and GO@SiO2 nanoparticles for dye rejection applications

In the textile industry, a high-efficiency dye removal is demanded to recycle wastewater. In this study, we decide to report the fabrication of high-performance mixed matrix nanofiltration PVDF membranes (MMMs) through the incorporation of different loading amounts of PVDF-g-PMMA copolymer and GO and GO@SiO2 (GS) nanoparticles separately and in coupled with each other. This copolymer was synthesized by grafting methyl methacrylate monomers onto polyvinylidene fluoride (PVDF) via the atom transfer radical polymerization method (ATRP), and graphene oxide@SiO2 was synthesized by using the modified hummer method, followed by the addition of SiO2 to the as-prepared GO nanosheets. The PVDF/PVDF-g-PMMA/Graphene Oxide@SiO2 membrane with optimum properties not only resulted in a high dye rejection of above 99% for Crystal Violet (CV) and Direct yellow (DY) dyes, but also led to a remarkable enhancement in water Flux from 1.96 L/m2·h·bar, for the neat PVDF, to 2.5 L/m2·h·bar, for the optimum PVDF/PVDF-g-PMMA/Graphene Oxide@SiO2 membrane, owing to the addition of the hydrophilic PVDF-g-PMMA copolymer and Graphene Oxide@SiO2 nanoparticles to the PVDF membrane matrix. Furthermore, the durability and antifouling abilities of the optimum membrane were also investigated, by which a significant performance was obtained.

Graft Copolymerization of Methyl Methacrylate and Vinyltriethoxysilane onto Natural Rubber

Preparation and characterization of natural rubber grafted with methyl methacrylate (MMA) and vinytriethoxysilane (VTES) were performed in the present work. Graft copolymerization of methyl methacryate was carried out in latex stage, and VTES was added during the graft copolymerization of MMA. FTIR and NMR spectroscopy were used to investigate the structure of graft copolymer and determination of conversion and grafting efficiency of MMA. It confirmed that the poly(methyl methacrylate) (PMMA) and silica particles (PVTES) were successfully formed in NR-graft-PMMA-PVTES graft copolymer. Conversions of MMA were about 90-100%; however, MMA grafting efficiency decreased as the MMA concentrations increased. Tensile property of NR-graft-PMMA-PVTES was found to improve compared with that of pure NR.

Zinc oxide enhancing hydrophilicity to [polytetrafluoroethylene-graft-poly(methyl methacrylate)]-graft-poly(2-(diethylamino)ethyl methacrylate) films

The low reactivity of polytetrafluoroethylene (PTFE) switches up through grafting reactions with acrylic monomers such as methyl methacrylate (MMA) and 2-(diethylamino)ethyl methacrylate (DEAEMA). (PTFE-g-PMMA)-g-PDEAEMA copolymer enhances its hydrophilic behavior through the coating of ZnO. Co-60 is used as the radical initiator source to perform a graft copolymerization through a two-step route, first using pre-irradiation oxidative to graft MMA, followed by direct irradiation to graft DEAEMA. Experimental parameters dose, solvent, and monomer concentration are studied. The characterization by infrared spectroscopy (FTIR-ATR), Raman spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA), is complemented by physicochemical studies of swelling and drop water contact angle. The ZnO-loaded (PTFE-g-PMMA)-g-PDEAEMA films are structured for multifunctional aims, as expected for their organic/inorganic composition.

Surface functionalization of ethylene–tetrafluoroethylene copolymer film with poly(methyl methacrylate) via chemical radical polymerization

The surface of a poly(ethylene-co-tetrafluoroethylene) (ETFE) film was modified by grafting of methyl methacrylate (MMA) by using diethyl(1,10-phenanthroline N1,N10)zinc (Phen-DEZ) and oxygen molecules as the radical initiator. Fourier transform infrared (FT-IR) spectra and Raman spectra of polymethylmethacrylate-grafted-ETFE (ETFE-g-PMMA), showed absorption peaks attributed to carbonyl functionalities. And the thermal decomposition of ETFE-g-PMMA was observed in two stages. The first weight loss step was due to the disruption of the grafted PMMA polymer, while the second degradation step was likely due to thermal disruption of ETFE itself. These results provide clear evidence of PMMA grafting onto ETFE film. The grafting yield of MMA was found to be affected by the polymerization temperature, reaction time, and concentration of Phen-DEZ. Analysis of the surface morphology of the film by atomic force microscopy (AFM) suggests that MMA was grafted on the surface of the ETFE film. In addition, the water contact angle on the hydrophobic surface of the ETFE film changed from 94.6° to 65.5° depending on the graft of PMMA, resulting in hydrophilicity. Moreover, the results of the dyeing experiment showed that only the surface of the ETFE film was decorated with MMA and the interior was unchanged.

Hydrogel of gelatin in the presence of graphite for the adsorption of dye: Towards the concept for water purification

Gelatin grafted environment-friendly hydrogel composite was utilized to perform the effective adsorption of methyl violet (MV) dye. Due to non-toxic, high surface zone and biodegradability, gelatin has received considerable attention for sustainable applications. Gelatin grafted methyl methacrylate (GE-g-MMA) hydrogels were prepared through the microwave-assisted green method. The GE-g-MMA hydrogel showed the highest swelling of 1039.4 %. Graphite (Gph) was introduced in GE-g-MMA hydrogel matrix to construct gelatin grafted methyl methacrylate/graphite (GE-g-MMA/Gph) hydrogel composite for adsorptive removal of poisonous methyl violet (MV) dye from water. The GE-g-MMA hydrogel and GE-g-MMA/Gph hydrogel composite were described through FTIR, XPS, SEM, Raman, XRD, TGA and BET techniques. Various adsorption factors like adsorbent dose, % removal of dye, contact period and solution pH were examined to develop ideal adsorption conditions. The GE-g-MMA/Gph hydrogel composite exhibited high adsorption efficiency of 99.9 % in 40 min (pH 9, MV: 50 mg L−1, adsorbent dose: 20 mg, MV volume: 20 ml). Experimental analysis results revealed that the synthesized GE-g-MMA/Gph hydrogel composite has a high capacity to remove MV molecules from aqueous solution at 25 °C. The values of the regression coefficient (R2) in case of Frendluich (0.999), Langmuir (0.978), Dubinin-Radushkevitch (0.936) and Temkin (0.931) clearly showed that the Freundlich isotherm fitted best to the adsorption process and pseudo-first-order kinetics demonstrated the better fit of adsorption with highest R2 (0.935). The GE-g-MMA/Gph hydrogel composite is economical, after six regeneration cycles, the adsorption efficiency of 95.8 % has been maintained.

Adhesion performance of UHMWPE fiber treated with polyethylene wax grafted methyl methacrylate alone or in conjunction with silane coupling agent

To improve the interfacial adhesion between ultrahigh molecular weight polyethylene (UHMWPE) fiber and epoxy resin, the fiber were treated with polyethylene wax grafted methyl methacrylate (PEW-g-PMMA) alone or in combination with silane coupling agent. The factors affecting the interfacial bond property of fiber, e.g. grafting rate, coating temperature, concentration of silane coupling agent were studied. The single-fiber pull-out tests showed that compared with the pristine UHMWPE fiber, the pull-out strength of 9 wt% PEW-g-PMMA treated fiber had increased by 45.11%, and the pull-out strength of 9 wt% PEW-g-PMMA/12 wt% silane coupling agent treated fiber had increased by 77.97%. The pull-out strength of fiber increased with the increase of temperature and grafting rate. Infrared analysis indicated that several polar groups were introduced onto the fiber surface through coating treatment. SEM analysis showed that the surface of treated fibers became rougher. Contact angle tests manifested that the functional coating was conductive to improve the wettability of fiber. Tensile testing and XRD results showed that the processing procedure almost had no effect on the crystallinity and mechanical properties of UHMWPE fibers. Finite element analysis showed that the presence of functional coating can improve the ability of the interface to resist damage.

Response surface optimized free radical grafting of methyl methacrylate on de-lignified rice straw for evaluating its application potential as flame retardant roofing material

The main objective of this investigation is to convert chemically bi-step pre-treated rice straw encompassing delignification and inorganic materials loading into a low cost roofing material by graft copolymerization of methyl methacrylate (MMA) via free radical mechanism. Central composite design (CCD) process utilizing response surface methodology (RSM) approach was adopted for the optimization of time duration, concentration of methyl methacrylate and reaction temperature (three-independent factors) at five levels. Optimization of the procedure was done by an estimated regression model (quadratic) in combination with an analysis of variance (ANOVA) depicting how the independent test variables have a comparative impact. Contour plots (2D) as well as response surface (3D) plots helped in investigating the cumulative interactions between the variables critical to optimization as well as in deciphering under which conditions optimal grafting can occur. Percentage of grafting (%G) was the response variable, which was a dependent output variable. A quadratic response surface model, according to estimated values could then be developed to relate every independent variable to percentage of grafting (%G). Optimal conditions projected by RSM were 3.99 cc amount of monomer, 119.85 min duration of time and 62.89 °C grafting temperature. At this combination, the highest percentage of grafting of 50.24% was predicted, with desirability = 1.00, the observed result indicates perfect reproducibility of the experiment. This theoretical value was compared with experimental result and the observed result is 50.68% which is very close to the software predicted value. The response surface quadratic model adequacy was satisfactory with the coefficient of regression of 0.9815. According to the Design-Expert software this predicted value of regression coefficient confirmed the accuracy of model fitness with the observed experimental data.

Impact of γ-rays on constructional, optical and thermal behavior of alkaline and non alkaline low density polyethylene

ABSTRACT In this study, we investigated the graft copolymerization of methyl methacrylate (MMA) onto low-density polyethylene (LDPE) in the presence of aniline as an inhibitor by gamma radiation. An alkaline treatment was carried out for the prepared graft copolymer. The structural properties of the prepared samples were examined via X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD peaks were slightly shifted, indicating an interaction between MMA and the polyethylene matrix. The morphology of the samples confirmed the homogenous grafted phase scattered onto the LDPE surface. Analysis of the absorption spectra indicated an allowed indirect transition mechanism. The Urbach energy (EU) results showed that the value of the EU for grafted LDPE was found to be higher than that of pure LDPE—up to 15 kGy irradiation dose, although this value decreases upon grafting. However, the value of the EU for alkaline-treated grafted films decreases systematically by increasing the degree of grafting. The thermogravimetric analysis (TGA) of the sample indicated that the thermal stability of LDPE samples is significantly changed by grafting MMA onto it. Horowitz and Metzger's models were utilized to measure the activation energy of the thermal decomposition of all samples.

Improvement of interfacial interaction in impregnated wood via grafting methyl methacrylate onto wood cell walls

Abstract Improving the interaction between the wood cell wall and a modifying agent is fundamental to enhancing the efficacy of wood modification. The extent of interaction is, nevertheless, difficult to evaluate due to the highly heterogeneous nature of the modified wood. In this study, methacryl groups were grafted onto the wood cell wall polymers, via the reaction between 2-isocyanatoethyl methacrylate (IEMA) and hydroxyl groups, to improve their compatibility and reactivity. Subsequently, methyl methacrylate (MMA) was introduced into methacrylated wood and copolymerized with the bonded methacryl groups. The distribution of IEMA and poly MMA (PMMA) in the wood cell walls was investigated by scanning electron microscopy (SEM) and confocal Raman microscopy. The results showed that MMA penetrated the wood cell walls and formed strong interfacial interaction, which was confirmed by confocal Raman microscopy combined with principal component analysis (PCA). With copolymerization, the highest anti-swelling efficiency (ASE) (57%) was achieved, because of the effect of methacrylation. Compared to the reference, the water resistance and hardness were significantly improved. In addition, the dynamic wettability was also altered largely due to copolymerization.

Getting Graft Cellulose Copolymers and Acrylic Monomers

Graft copolymers of acrylic monomers with cotton cellulose were obtained. The dependence of the degree and efficiency of grafting of acrylic acid and methyl methacrylate to cellulose on the concentration of monomer and initiator was investigated. Pre-adsorption of the initiator in the macromolecules of cellulose leads to an increase in the efficiency of the grafting. The efficiency of grafting is higher in those systems in which the initiator used is insoluble in the monomer solvent. Absorption of cellulose with an aqueous solution of the initiator - potassium persulfate, followed by removal of water was done. The advantage of using a water-soluble initiator is that during subsequent processing with a solution of monomer in an organic solvent, the desorption of the active centers does not occur. An increase in the concentration of theinitiator leads to an increase in the degree of grafting, a slight increase in the efficiency of the grafting, a significant decrease in the degree of polymerization and the molecular weight of the graft chains. In a heterogeneous process, an increase in the efficiency of grafting with an increase in the concentration of theinitiator is promoted by the additional adsorption interaction of the initiator molecules with the surface of cellulose. With an increase in the concentration of monomers, the overall degree of conversion slightly increases, the efficiency of grafting slightly decreases, the degree of grafting and the molecular weight of the graft chains increase significantly. The mechanism of graft copolymerization was investigated by comparative analysis of the IR and PMR spectra of cellulose, potassium persulfate, acrylic monomers and products of their interaction. Due to the results of spectroscopic studies, a scheme of graft copolymerization reactions has been proposed. The active centers of graft copolymerization are formed as a result of the reductive interaction of potassium persulfate, water and cellulose macromolecules.