Methyl Methacrylate Content Research Articles

Poly(HEMA-co-MMA) Hydrogel Scaffold for Tissue Engineering with Controllable Morphology and Mechanical Properties Through Self-Assembly.

Poly(2-hydroxyethyl methacrylate) (PHEMA) has been widely used in medical materials for several decades. However, the poor mechanical properties of this material have limited its application in the field of tissue engineering. The purpose of this study was to fabricate a scaffold with suitable mechanical properties and in vitro cell responses for soft tissue by using poly(HEMA-co-MMA) with various concentration ratios of hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA). To customize the concentration ratio of HEMA and MMA, the characteristics of the fabricated scaffold with various concentration ratios were investigated through structural morphology, FT-IR, mechanical property, and contact angle analyses. Moreover, in vitro cell responses were observed according to the various concentration ratios of HEMA and MMA. Consequently, various morphologies and pore sizes were observed by changing the HEMA and MMA ratio. The mechanical properties and contact angle of the fabricated scaffolds were measured according to the HEMA and MMA concentration ratio. The results were as follows: compressive maximum stress: 254.24-932.42 KPa; tensile maximum stress: 4.37-30.64 KPa; compressive modulus: 16.14-38.80 KPa; tensile modulus: 0.5-2 KPa; and contact angle: 36.89-74.74°. In terms of the in vitro cell response, the suitable cell adhesion and proliferation of human dermal fibroblast (HDF) cells were observed in the whole scaffold. Therefore, a synthetic hydrogel scaffold with enhanced mechanical properties and suitable fibroblast cell responses could be easily fabricated for use with soft tissue using a specific HEMA and MMA concentration ratio.

Mechanically Adaptable High‐Performance p(SBMA‐MMA) Copolymer Hydrogel with Iron (II/III) Perchlorate for Wearable Thermocell Applications

AbstractQuasi‐solid‐state thermocells (QTECs) show promise as a power source for wearable devices by converting body heat into electricity. While significant progress has been made with p‐type elements for QTECs, challenges remain with their n‐type counterparts. Here, a high‐performance n‐type QTEC element is presented, using a copolymer hydrogel that outperforms conventional p‐type elements. This copolymer hydrogel combines hydrophilic zwitterionic sulfobetaine methacrylate (SBMA) for ionic conduction and hydrophobic methyl methacrylate (MMA) for structural stability. By increasing the MMA content from 35 to 100 wt.%, versatile control is achieved over the hydrogel's elastic modulus (72 kPa to 127.7 MPa) and tensile strength (54 kPa to 6.7 MPa). A high mechanical toughness of 7.2 MJ m−3 is also achieved at 68 wt.% MMA. The mechanically robust and high toughness p(SBMA‐MMA) hydrogel is then immersed in Fe(ClO4)2/3 solutions of different concentrations to evaluate its performance as an n‐type QTEC element. The hydrogel with 0.8 M Fe(ClO4)2/3 exhibits a high ionic Seebeck coefficient of −1.7 mV K−1, a power density of 1.1 mW m−2 K−2, and an elastic modulus of 1.6 MPa, which is similar to that of human skin. Finally, the optimized n‐type p(SBMA‐MMA) hydrogels demonstrate the potential application for wearable devices.

The effect of weighting on the color appearance of dyed silk fabric

The weighting process may change the color appearance of silk. The objective of the present study is to evaluate the effect of weighting with methyl methacrylate (MMA) on the color appearance of silk fabric using the response surface method. For this purpose, a CCD design was used to investigate the effect of methyl methacrylate monomer concentration and dye concentration on color appearance and percentage of weight gain of silk fabric. Analysis of variance, response surface, and contour plots of the colorimetric characteristics of the weighted silk fabric show that the methyl methacrylate concentration has a significant effect on color parameters such as L*, a*, b*, C*, and hue angle of the weighted silk fabric. The results indicate that the weighting process changes the color of silk fabric.

Synthesis and properties of AM/AMPS/MMA and cationic monomer copolymer flooding agent

Abstract A novel hydrophobic association copolymer (PAMA) was synthesized by incorporating acrylamide (AM), 2-acrylamide-2-methylpropanesulfonic acid (AMPS), cationic monomer (MEDDA), and methyl methacrylate (MMA). The properties of MMA copolymers with varying contents were analyzed using infrared spectroscopy, nuclear magnetic resonance spectroscopy, and scanning electron microscopy. Optimal overall performance of the solution was achieved when the MMA content reached 1.4 % w/w. Compared to pure PAAM (without MMA), the PAMA-1.4 % polymer exhibited superior viscoelasticity, temperature resistance, and shear resistance. This enhancement in PAMA performance can be attributed to the significant inhibition of intermolecular water film formation within the polymer matrix by MMA, effectively improving and regulating solution solubility while strengthening molecular chain interactions and enhancing the structural network strength of PAMA polymers. Additionally, the inclusion of MMA transformed rock surfaces from non-wetting to wetting conditions, thereby greatly improving oil displacement efficiency. In displacement experiments, PAMA-1.4 % performed better in terms of enhanced oil recovery, the recovery rate of 0.1 % w/w PAMA-2.4 % solution is only 7.78 %, while the recovery rate of 0.1 % w/w PAMA-1.4 % solution is 13.06 %.

Efficient adsorption and rapid electrochemical degradation of methyl methacrylate (MMA) by three-dimensional nanostructured carbon anode

Methyl methacrylate (MMA) is a widely used oxygen-containing volatile organic compound, functioning as both an organic solvent and additive. Therefore, the advancement of effective methods for MMA removal is of great significance. In this study, three-dimensional nanostructured carbon (CNTs/CC) anode materials were prepared through the in-situ growth of carbon nanotubes (CNTs) on carbon cloth (CC) using chemical vapor deposition (CVD). The prepared material showed outstanding adsorption-electrocatalytic degradation performance towards MMA, with a saturated adsorption capacity of 2033 mg·g−1 and complete degradation achieved after 90 min of electrification at a 100 mg·L−1 MMA concentration. The electrochemically active surface area increased to 29.8 cm2 with an Rs value of 2.35 Ω for the CNTs/CC-2 anode material, leading to enhanced ·OH generation capability and faster degradation rates. The material also exhibited excellent reusability over thirteen cycles of adsorption-electrochemical degradation of MMA, with a degradation efficiency consistently above 92 %. This research provides valuable insights for developing new materials and technologies for MMA degradation.

Preparation and Characterization of Poly(Methyl Methacrylate) Grafted Natural Rubber Latex Films

Poly(methyl methacrylate) (PMMA) grafted natural rubber (NR) latex was successfully prepared and solely exploited even at high MMA concentration (1.5 mol/kg-rubber) to make coherent and uniform vulcanized films without blending with other polymer to achieve excellent physical properties. High ammonia natural rubber (HANR) latex was subjected to graft-copolymerization with methyl methacrylate (MMA) monomer in the presence of tert-butyl hydroperoxide (TBHP) and tetraethylenepentamine (TEPA). High conversion, i.e., 85.12 mol%, and grafting efficiency, i.e., 92.70 mol%, were obtained at 1.5 mol/kg-rubber MMA. The resulting gross PMMA grafted NR (1.5PMMA) latex was then compounded, dipped, and vulcanized to produce thin films. The tensile strength and modulus at 300 percent (M300) of vulcanized 1.5PMMA film were superior to vulcanized HANR film by 1-fold. While elongation at break (EB) was identical to each other due to the high gel content in both vulcanized films. Besides, the vulcanized 1.5PMMA film absorbed less oil compared to HANR film. The thermal stability of vulcanized 1.5PMMA film was found to be higher than that of vulcanized HANR film. Hence, it can be deduced that controlling the graft-copolymerization of PMMA in NR latex is the key to produce coherent thin films with improved properties at higher PMMA content.

Effect of methyl methacrylate concentrations on surface and thermal analysis of composite polymer polymethylmethacrylates with mesogen reactive RM82

ABSTRACT This research report of the synthesis of composite polymers from liquid crystal mesogen reactive (RM82) monomers with Methyl methacrylate (MMA). The purpose of this research is analysis the effect concentration of MMA on the surface and thermal of the composite polymer PMMA-RM82. The result of the morphological analysis of composite surfaces performed by polarization optical microscopy (POM) technique showed liquid crystal textures affected composition from two monomers. SEM images show that the surface of the RM82 liquid crystal has a shape resembling fibrous and blade-like crystals with a length of up to 10 μm (micrometers). Analysis thermal showed the heat released by the PMMA-RM82 increased with the increase in MMA weight percent. This affects the rapid crystallization process of PMMA-RM82 which of concentration MMA 30%-RM82 the heat released is almost twice as much as the heat released by MMA 5%-RM82. The absence of PMMA and RM82 peaks both endothermic and exothermic in PMMA-RM82 samples indicates that polymerization has occurred and a new product has formed. Analysis structure molecule by FTIR found that the IR spectral form of each variation in the weight percent of MMA was almost the same, but there was a spectral shift that showed that polymerization had occurred in PMMA-RM82 which was characterized by a reaction to the free radical C=C bond released by the photoinitiator. XRD pattern of composite PMMA-RM82 showed the peaks formed are located at scattering angles similar to RM82 but there is a decrease in intensity as the percent weight of MMA increases.

Depolymerization of PMMA-Based Dental Resin Scraps on Different Production Scales

This research explores the depolymerization of waste polymethyl methacrylate (PMMAW) from dental material in fixed bed semi-batch reactors, focusing on three production scales: laboratory, technical and pilot. The study investigates the thermal degradation mechanism and kinetics of PMMAW through thermogravimetric (TG) and differential scanning calorimetry (DSC) analyses, revealing a two-step degradation process. The heat flow during PMMAW decomposition is measured by DSC, providing essential parameters for designing pyrolysis processes. The results demonstrate the potential of DSC for energetic analysis and process design, with attention to standardization challenges. Material balance analysis across the production scales reveals a temperature gradient across the fixed bed negatively impacting liquid yield and methyl methacrylate (MMA) concentration. Reactor load and power load variables are introduced, demonstrating decreased temperature with increased process scale. The study identifies the influence of temperature on MMA concentration in the liquid fraction, emphasizing the importance of controlling temperature for efficient depolymerization. Furthermore, the research highlights the formation of aromatic hydrocarbons from the remaining char, indicating a shift in liquid composition during the depolymerization process. The study concludes that lower temperatures below 450 °C favor liquid fractions rich in MMA, suggesting the benefits of lower temperatures and slower heating rates in semi-batch depolymerization. The findings contribute to a novel approach for analyzing pyrolysis processes, emphasizing reactor design and economic considerations for recycling viability. Future research aims to refine and standardize the analysis and design protocols for pyrolysis and similar processes.

Development of Water-Resistant Autohesive Strength of Polyethylene Plates with Photografting of Alkyl (Meth)Acrylates

This study aims to confer autohesive strength to polyethylene (PE) plates by swelling the grafted layers, which were formed on the PE plates grafted with alkyl (meth)acrylate monomers, with 1,4-dioxane, and subsequently heat-pressing them. For the methyl methacrylate (MMA)-grafted PE (PE-g-PMMA) plates, the location of grafting was restricted to the outer surface region and the grafted layer with higher densities of grafted PMMA chains was composed. When the grafted PE plates were immersed in 1,4-dioxane, and then heat-pressed while applying the load, autohesion was developed. The substrate failure was observed for the PE-g-PMMA plates and the grafted amount at which the substrate failure was observed decreased with the procedures that decreased the methanol concentration of the solvent, the MMA concentration, the grafting temperature, and the heat-press temperature, and/or increased the load. The lowest grafted amount of 45 μmol/cm2 for the substrate failure was obtained under the conditions where the PE-g-PMMA plate prepared at 0.75 M and 60 °C in a 70 vol% aqueous methanol solution was heat-pressed at 60 °C while applying the load of 2.0 kg/cm2. The swelling of the grafted layers with 1,4-dioxane considerably contributed to the development of autohesion, bringing the inter-diffusion of grafted PMMA chains and coincident entanglement of grafted PMMA chains during the heat-pressing. The fact that the substrate failure occurred indicates that an autohesive strength higher than the ultimate strength of the used PE plate was obtained. Our approach provides a novel procedure to develop the water-resistant autohesion of PE plates.

Water temperature for fabrication of autopolymerizing polymethyl methacrylate (PMMA) interim fixed restoration affects cytotoxicity and residual methyl methacrylate (MMA)

Background/purposeClinically, dentists are suggested to immerse autopolymerizing interim fixed restorations in hot water during fabrication. However, this suggestion, without including the best temperature, mostly comes from clinical experience instead of scientific evidence. This in vitro study evaluated the effect of water temperature on the cytotoxicity of interim partial fixed dental prostheses (FDPs) and examined its correlation with residual MMA. Materials and methodsTempron was chosen as the autopolymerizing polymethyl methacrylate material. Tempron was mixed and then soaked in water at different temperatures, except control group (Controlair) was not being soaking in water. The specimens were incubated with conditioned medium. The concentration of residual MMA was determined by liquid chromatography-tandem mass spectrometry (LC-MS-MS). The cell viability of human gingival fibroblasts (HGFs) was evaluated by MTT assay. ResultsThe 60 °C and 80 °C groups exhibited significantly higher cell viabilities than those of the other groups (P < 0.05) at 48 and 72 h. The concentration of residual MMA was highly correlated with this outcome: the higher the concentration of residual MMA detected in the eluates, the poorer the cell viability was; the longer the incubation time was, the stronger the correlation was between the concentration of residual MMA and the cell viability. ConclusionAutopolymerizing PMMA interim FDPs that are polymerized in water up to at least 60 °C could reduce cell toxicity. Higher water temperature could certainly decrease the amount of residual MMA, which is closely correlated with the outcome of cell viability.

Methacrylate Cationic Nanoparticles Activity against Different Gram-Positive Bacteria.

Nanotechnology is a developing field that has boomed in recent years due to the multiple qualities of nanoparticles (NPs), one of which is their antimicrobial capacity. We propose that NPs anchored with 2-(dimethylamino)ethyl methacrylate (DMAEMA) have antibacterial properties and could constitute an alternative tool in this field. To this end, the antimicrobial effects of three quaternised NPs anchored with DMAEMA were studied. These NPs were later copolymerized using different methylmethacrylate (MMA) concentrations to evaluate their role in the antibacterial activity shown by NPs. Clinical strains of Staphylococcus aureus, S. epidermidis, S. lugdunensis and Enterococcus faecalis were used to assess antibacterial activity. The minimal inhibitory concentration (MIC) was determined at the different concentrations of NPs to appraise antibacterial activity. The cytotoxic effects of the NPs anchored with DMAEMA were determined in NIH3T3 mouse fibroblast cultures by MTT assays. All the employed NPs were effective against the studied bacterial strains, although increasing concentrations of the MMA added during the synthesis process diminished these effects without altering toxicity in cell cultures. To conclude, more studies with other copolymers are necessary to improve the antibacterial effects of NPs anchored with DMAEMA.

Preparation of polyacrylamide-poly(methyl methacrylate) emulsion for enhancing the adhesion of polyester/cotton yarn

Polyacrylamide-poly(methyl methacrylate) copolymer emulsion was synthesized by prepolymerization of methyl methacrylate, and then copolymerization with acrylamide. The final yield of polyacrylamide-poly(methyl methacrylate) emulsion can be up to 93.69%, and its molecular weight was 11.2 × 104 Da, as well as the characteristic peaks of the ester group (–COO) of methyl methacrylate and amide group (–NH2) of acrylamide appeared on its structure. The component content of acrylamide and methyl methacrylate from polyacrylamide-poly(methyl methacrylate) can be effectively controlled by adjusting the prepolymerization conversion of methyl methacrylate. The polyacrylamide-poly(methyl methacrylate) emulsion exhibited spherical morphology, and its particle size was 50–130 nm. Moreover, the correlation between particle size and the film-forming property of the polyacrylamide-poly(methyl methacrylate) emulsion was studied. It was concluded that when the particle size was small, the aggregation ability among molecules was strong, and endowed polyacrylamide-poly(methyl methacrylate) emulsion film with more action during the stretching process, making it able to withstand the larger tensile opposite force. Interestingly, the polyacrylamide-poly(methyl methacrylate) emulsion can reinforce the adhesion of polyester/cotton yarn. These benefit from the strong hydrogen bond between polyacrylamide and cotton yarn and poly(methyl methacrylate) had a similar ester structure to polyester fibers. This work solves the problems of difficult copolymerization between acrylamide and acrylate, it provides a new way to develop acrylamide-based copolymer adhesive.

Evaluating Indoor Air Phthalates and Volatile Organic Compounds in Nail Salons in the Greater New York City Area: A Pilot Study.

The Greater New York City area ranks highest in the United States in the number of nail salon technicians, primarily Asian immigrant women. Nail salon technicians are exposed to toxic phthalates and volatile organic compounds daily in nail salons. The purpose of this pilot study was to measure a mixture of phthalates and volatile organic compounds in nail salons in the Greater New York City area, and to characterize work-related determinants of indoor air quality in these nail salons. Working with four Asian nail salon organizations in the Greater New York City area, we measured indoor air phthalates and volatile organic compounds at 20 nail salons from February to May 2021 using silicone wristbands and passive samplers, respectively. Nail salon characteristics were also examined. We measured six phthalates and 31 volatile organic compounds. Di(2-ethylhexyl) phthalate and Diethyl phthalate had the highest concentrations among the six phthalates measured. Concentrations of toluene, d-limonene, methyl methacrylate, and ethyl methacrylate were higher than that of the rest. Manicure/pedicure tables, the number of customers per day, and application of artificial nail (acrylic) services were positively associated with the levels of phthalates and volatile organic compounds. Given the large number of people employed in the nail industry and the even larger number of customers visiting such establishments, exposures to these toxic chemicals are likely to be widespread.

Preparation of Polyurethane/Acrylate Composite Emulsion for Inkjet Printing

Water-borne polyurethane/acrylate (WPUA) emulsion was prepared through emulsion polymerization between vinyl terminated waterborne polyurethane (WPU) and methyl methacrylate (MMA) in this research. Thermogravimetric Analysis (TGA), transmission electron microscopy (TEM), contact angle analysis, and particle size distribution analysis were employed to investigate the performance of the prepared emulsion and coatings with various content of MMA content. The results demonstrated that the thermal resistance, water resistance, and hardness of the prepared WPUA coatings were enhanced by the introduction of the MMA monomer. The contact angle (CA) and particle size of WPUA emulsion increased with the increase of MMA content. Meanwhile, the water-borne inkjet printing ink was prepared using WPUA emulsion as binder resin, and the printing test result showed that the prepared inkjet ink has good printability and color rendering, indicating that WPUA emulsion has great application prospects in the field of inkjet printing.

Analysis of the residual monomer content in milled and 3D-printed removable CAD-CAM complete dentures: an in vitro study

ObjectiveThe study aimed to quantitatively evaluate the elution of methylmethacrylate from CAD-CAM manufactured removable complete dentures (RCDs) using high performance liquid chromatography (HPLC). MethodsThirty-two RCDs were manufactured following either the CNC-milling (Milled: n=8) or the 3D-printing (n=24) protocols. The 3D-printed dentures were further categorized into three groups based on their post-production rinsing cycles [Extended wash cycle (EWC), Standard wash cycle (SWC), and SWC with an additional Durécon coating (SWC2)]. HPLC was used to evaluate the methylmethacrylate concentrations (MMCs) eluted from the dentures in each group for different time periods (1, 2, 4, 8, and 24 hours). Mean and standard deviations were calculated for the MMCs; data was verified for normal distribution, ANOVA and post hoc tests were applied for statistical analyses (⍺=0.05). ResultsThe HPLC revealed that all the denture groups recorded some amounts of MMCs, with significant differences [F (3, 31) = 23.646, p<0.0001]. The milled denture group had the highest MMCs at 24 hours when compared to the EWC (p<0.0001), SWC (p=0.001), and SWC2 (p<0.0001) denture groups. SWC had a higher MMC than EWC (p=0.032) and SWC2 (p=0.015). No differences were found in MMCs when comparing EWC and SWC2 (p=0.989). ConclusionMethylmethacrylate concentrations were significantly lower in 3D-printed RCDs than in milled RCDs when using the resins employed in this study. Furthermore, the MMCs can be further decreased in 3D-printed RCDs when coated with an additional thin protective layer (Durécon) by following the manufacturer-recommended rinsing protocol or when an extended isopropanol wash cycle is adopted.

Health risk assessment of volatile organic compounds exposure among nail salon workers in Vietnam

Purpose The objective of this study is to assess the carcinogen and non-carcinogen risks due to exposure to volatile organic compounds including methyl methacrylate (MMA), benzene, toluene, and xylene among Vietnamese nail salon workers, using probabilistic health risk assessment. Methods This study applied the probabilistic health risk assessment framework to assess the health risk due to exposure to four types of volatile organic compounds among nail salon workers. Forty-two passive personal samples of full-shift female nail workers from 15 salons in Da Nang city were monitored and analyzed by GC-FID in the Thammasat laboratory. Exposure parameters were collected by interviewing nail salon workers. Monte Carlo simulation was used to characterize the risk and its uncertainty. Results The mean of concentrations of MMA, benzene, toluene, and xylene were 20.62, 0.21, 2.49, and 0.58 mg m−3, respectively. The 95th percentile hazard quotients calculated for MMA, benzene, toluene, and xylene were 33.14, 7.49, 0.54, and 2.07, respectively. The 95th percentile lifetime cancer risk for benzene was 198 times higher than the EPA recommendation for cancer risk (10−6). Conclusions Non-cancer risks from exposure to MMA, benzene, and xylene were many times higher than the acceptable limit, which indicated a possible risk of adverse health effects among nail salon workers. Nail salon workers may also be at risk of leukemia or cancer of the blood-forming organs because the cancer risk due to exposure to benzene is higher than the recommended level.

Process Analysis of PMMA-Based Dental Resins Residues Depolymerization: Optimization of Reaction Time and Temperature

This work aims to optimize the recovery of methyl methacrylate (MMA) by depolymerization of polymethyl methacrylate (PMMA) dental resins fragments/residues. In order to pilot the experiments at technical scale, the PMMA dental resins scraps were submitted by thermogravimetric analysis (TG/DTG/DTA). The experiments were conducted at 345, 405, and 420 °C, atmospheric pressure, using a pilot scale reactor of 143 L. The liquid phase products obtained at 420 °C, atmospheric pressure, were subjected to fractional distillation using a pilot scale column at 105 °C. The physicochemical properties (density, kinematic viscosity, and refractive index) of reaction liquid products, obtained at 345 °C, atmospheric pressure, were determined experimentally. The compositional analysis of reaction liquid products at 345 °C, 30, 40, 50, 60, 70, 80, and 110 min, at 405 °C, 50, 70, and 130 min, and at 420 °C, 40, 50, 80, 100, 110, and 130 min were determined by GC-MS. The morphology of PMMA dental resins fragments before and after depolymerization was performed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX). The experiments show that liquid phase yields were 55.50%, 48.73%, and 48.20% (wt.), at 345, 405, and 420 °C, respectively, showing a first order exponential decay behavior, decreasing with increasing temperature, while that of gas phase were 31.69%, 36.60%, and 40.13% (wt.), respectively, showing a first order exponential growth, increasing with temperature. By comparing the density, kinematic viscosity, and refractive index of pure MMA at 20 °C with those of liquid reaction products after distillation, one may compute percent errors of 1.41, 2.83, and 0.14%, respectively. SEM analysis showed that all the polymeric material was carbonized. Oxygenated compounds including esters of carboxylic acids, alcohols, ketones, and aromatics were detected by gas chromatography/mass spectrometry (GC-MS) in the liquid products at 345, 405, and 420 °C, atmosphere pressure. By the depolymerization of PMMA dental resins scraps, concentrations of methyl methacrylate between 83.454 and 98.975% (area.) were achieved. For all the depolymerization experiments, liquid phases with MMA purities above 98% (area.) were obtained between the time interval of 30 and 80 min. However, after 100 min, a sharp decline in the concentrations of methyl methacrylate in the liquid phase was observed. The optimum operating conditions to achieve high MMA concentrations, as well as elevated yields of liquid reaction products were 345 °C and 80 min.

Designing of desired nanocomposite pressure-sensitive adhesives through tailoring the structural characteristics of polysilsesquioxane-acrylic core-shell nanoparticles

A series of novel nanocomposite pressure-sensitive adhesives (PSAs) made of core-shell nanoparticles has been designed with a diverse range of adhesion properties from general-purpose to high-shear adhesives. The PSAs were prepared by synthesis of polymethacryloxypropylsilsesquioxane (PSQ) nanoparticles and their encapsulation with an acrylic shell via semi-continuous emulsion polymerization. The effects of structural characteristics of the core-shell nanoparticles, i.e. composition of acrylic comonomers in the shell, shell thickness, and grafting density, on peel and shear strengths of the PSAs were scrutinized. Grafting of acrylic chains on the surface of PSQ nanoparticles led to an improvement in the peel and shear strengths due to enhancement in the dynamic mechanical moduli. Increase in the cohesive energy density of the PSAs through raising the methyl methacrylate content in the shell enabled designing of high peel and shear PSAs. Increasing the number of segments of the grafted chains present in the semi-dilute polymer brush (SDPB) region through 40% enlargement in the shell thickness of the nanoparticles decreased the peel and shear strengths. However, increasing the grafting density through a 4.5-fold rise in the core size and thus extension of the concentrated polymer brush region and elimination of SDPB region led to an extraordinary 1400-fold improvement in the shear strength. • Grafting of acrylic chains on PSQ enhanced peel and shear strengths simultaneously. • Optimization of cohesive energy density of shell enhanced peel and shear strengths. • Extension of semi-dilute polymer brush region deteriorated the shear strength. • Increase in grafting density led to an extraordinary improvement in shear strength.

Preparation of highly transparent poly(meth)acrylates with enhanced refractive indices by radical (co)polymerization of seleno(meth)acrylates

Over the years, selenium-containing polymers have attracted increasing interest as high-refractive index materials. In this study, two transparent high-refractive-index polymer series were prepared by the radical polymerization of phenyl selenomethacrylate (PhSeM) and phenyl selenoacrylate (PhSeA), and their copolymerization with methyl methacrylate (MMA). The refractive indices of the poly(PhSeM) and poly(PhSeA) homopolymer films were 1.6426 and 1.6519, respectively at 589 nm with Abbe numbers in the range 27.2–24.1, making them ideal monomers for improving the refractive indices of (meth)acrylate-based copolymers. By increasing the MMA content, the refractive indices of these copolymers were reduced from 1.6207 into 1.5181 with Abbe numbers in the range 25.7–53.1. Both homopolymers exhibited excellent transmittances (>94%) at the wavelength 400 nm. Moreover, owing to their higher MMA content, the selenium-containing copolymers exhibited a higher transparency (95–99%) than the homopolymers, which is highly desirable for optically transparent materials.

The influence of polymer on optical and thermal properties of nematic liquid crystals

Polymer is substance which consists of large number of molecules and plays a very important in our everyday life. In the present study the effect of different concentration of polymer Poly Methyl Methacrylate on the optical and thermal properties of nematic liquid crystal were investigated. The polymer was dispersed in the liquid crystal by polymerization induced phase separation method. The physical properties were investigated using differential scanning calorimetry and polarized optical microscopy. We found various textures according to the molecular order and orientation of the liquid crystal and polymer in constrained regions separated by phase boundaries. These composite materials can be used to enhance contrast ratio with more stability for display application and smart window.