PMMA Copolymer Research Articles

Exploration of the thermal and mechanical characteristics of polymethyl methacrylate-based copolymers: implications for wind turbine blades applications

Abstract Wind turbine (WT) blade fabrication typically employs thermosetting resins, whose recycling challenges post-retirement have resulted in environmental pressures. Thus, there is an urgent need to develop a low-viscosity, high-performance, and recyclable material with excellent mechanical properties that is compatible with WT fabrication processes, serving as a viable alternative to traditional epoxy resins. Poly(methyl methacrylate) (PMMA) resin is considered a promising candidate for replacing epoxy resins. However, the mechanical properties of PMMA still require improvement. In this study, we investigated the effects of introducing copolymerized monomers on the comprehensive performance of PMMA resin without affecting its viscosity, examining the influence of these copolymerized monomers on the material’s thermal and mechanical properties. Meanwhile, the mechanical properties of the synthesized PMMA-based copolymers were compared with those of blade-specific epoxy resin (WD0135). The results revealed that compared to WD0135, the flexural strength and modulus of the prepared PMMA copolymers significantly increased to 96.6 and 3158.6 MPa, respectively, with a tensile strength reaching 74.2 MPa. Consequently, this series of PMMA-based resins demonstrates immense potential for large-scale material part fabrication via casting techniques.

Fabrication of Permanent Antistatic PMMA Copolymer for Enhanced Antistatic and Mechanical Properties

Fabrication of Permanent Antistatic PMMA Copolymer for Enhanced Antistatic and Mechanical Properties

Quartz crystal microbalance gravimetry measurements of the sorption of trimethylaluminum into polystyrene and poly(methyl methacrylate)

The sorption behavior of metalorganic species into polymers is important in various gas-phase processes including vapor phase infiltration (VPI) which is used to transform organic polymers into organic-inorganic hybrid materials and area-selective deposition where various organic layers are used to prevent vapor deposition. In this work, we use in situ quartz crystal microbalance (QCM) gravimetry to measure the long-term mass uptake of TMA into polystyrene (PS) and compare it with that of poly (methyl methacrylate) [PMMA]. While TMA infiltration into PMMA, PS, and PMMA-PS copolymers is widely studied, a direct investigation of TMA's long term sorption behavior into pure PS has not previously been reported. During a 17.5 h TMA exposure step, PMMA is found to sorb 0.67–0.83 ng of TMA per nanogram of polymer while PS is found to sorb only 0.02 ng per nanogram polymer. These results clarify that the mechanism for low TMA infiltration into PS is a lack of sorption rather than rapid out-diffusion of the precursor. This result has implications ranging from designing impermeable layers for selective area deposition to predicting mass transport during vapor infiltration into ordered block copolymers. Here, the poor sorption of TMA into PS is utilized in a demonstration to pattern inorganic infiltration into PET films.

Revisiting the structure of copolymer via anionic hybrid copolymerization of methyl methacrylate and ε-caprolactone

Anionic hybrid copolymerization of vinyl and cyclic monomers provides a powerful strategy to synthesize heteropolymers. Yet, there are some open questions regarding its mechanism and the structure of the resulted polymer. We reported that the copolymer (Poly(MMA- co -CL)) of methyl methacrylate (MMA) and ε-caprolactone (CL) via such copolymerization was random. However, a recent study proposed that the copolymer might be simple graft one with poly(methyl methacrylate) (PMMA) as the main chain and poly(ε-caprolactone) (PCL) as the graft chain. In this study, we synthesized a model graft copolymer (PMMA- g -PCL) by using a combination of reversible complexation-mediated polymerization and ring-opening polymerization, and made comparison with Poly(MMA- co -CL) in their properties and hydrolysis. Differential scanning calorimeter (DSC) measurements show that the graft copolymer PMMA- g -PCL possesses two glass transitions and a melt peak. In contrast, Poly(MMA- co -CL) exhibits only one glass transition without a melt peak because it is amorphous, clearly indicating that it is random. Proton nuclear magnetic resonance ( 1 H NMR) measurements reveal that the hydrolysis of PMMA- g -PCL yields only PMMA oligomers. However, the hydrolyzed products of Poly(MMA- co -CL) consist of MMA and CL units. The facts further indicate that the copolymer Poly(MMA- co -CL) is random. Considering that the transesterification reactions are unavoidable in the anionic hybrid copolymerization, the copolymer should consist of random main chain and random branches. • The present study demonstrates that anionic hybrid copolymerization of MMA and CL generally yields random copolymer but not graft copolymer. • Transesterification is not the essential step in the anionic hybrid copolymerization, but it can cause branching of the copolymer. • The hybrid copolymer of MMA and CL consists random main chain and random branches.

Organic–inorganic hybrid strategy toward halogen‐free flame retardant, high transparent and reinforced poly(methyl methacrylate)

AbstractCopolymerization of methyl methacrylate (MMA) with flame retardant monomer is considered to be the most promising method for the preparation of transparent flame retardant poly (methyl methacrylate) (PMMA). However, the mechanical strength and heat resistance of the obtained flame retardant copolymers aren't satisfactory. In this work, the organic–inorganic hybrid PMMA copolymer is designed and synthesized by the ternary copolymerization of MMA, octavinyl silsesquioxane (V‐POSS) and phosphorus‐containing flame retardant monomer (DEP). V‐POSS hardly affects the transparency and flame retardancy of the copolymer, but can significantly improve the thermal stability and mechanical properties. When 0.4 mol% V‐POSS is copolymerized, the hybrid copolymer shows limiting oxygen index, heat release rate and visible light transmittance equivalent to the copolymer containing only DEP unit, and the initial decomposition temperature, storage modulus, flexural strength and impact strength are increased by 13°C, 21%, 11% and 23% respectively because of the cross‐linking structure and the enhancement of inorganic nanoparticles. This study illustrates the reinforcing and flame retardant effects of hybrid copolymers, and provides a novel strategy for the preparation of high‐performance flame retardant plexiglass.

Multicolor Nitrogen-Doped Carbon Quantum Dots for Environment-Dependent Emission Tuning.

Carbon quantum dots (CQDs) have potential applications in many fields such as light-emitting devices, photocatalysis, and bioimaging due to their unique photoluminescence (PL) properties and environmental benignness. Here, we report the synthesis of nitrogen-doped carbon quantum dots (NCQDs) from citric acid and m-phenylenediamine using a one-pot hydrothermal approach. The environment-dependent emission changes of NCQDs were extensively investigated in various solvents, in the solid state, and in physically assembled PMMA–PnBA–PMMA copolymer gels in 2-ethyl-hexanol. NCQDs display bright emissions in various solvents as well as in the solid state. These NCQDs exhibit multicolor PL emission across the visible region upon changing the environment (solutions and polymer matrices). NCQDs also exhibit excitation-dependent PL and solvatochromism, which have not been frequently investigated in CQDs. Most CQDs are nonemissive in the aggregated or solid state due to the aggregation-caused quenching (ACQ) effect, limiting their solid-state applications. However, NCQDs synthesized here display a strong solid-state emission centered at 568 nm attributed to the presence of surface functional groups that restrict the π–π interaction between the NCQDs and assist in overcoming the ACQ effect in the solid state. NCQD-containing gels display significant fluorescence enhancement in comparison to the NCQDs in 2-ethyl hexanol, likely because of the interaction between the polar PMMA blocks and NCQDs. The application of NCQDs-Gel as a solid/gel state fluorescent display has been presented. This research facilitates the development of large-scale, low-cost multicolor phosphor for the fabrication of optoelectronic devices, sensing, and bioimaging applications.

Varying the sequence distribution and hydrogen bonding strength provides highly Heat-Resistant PMMA copolymers

In this study we used free radical copolymerization of methyl methacrylate (MMA) and N-hydroxyphenylmaleimide (HPMI) to synthesize various poly(methyl methacrylate–co–N-hydroxyphenylmaleimide) (PMMA-co-PHPMI) random copolymers possessing high glass transition temperatures (Tg). FTIR and NMR spectroscopy, mass spectrometry, and differential scanning calorimetry (DSC) confirmed the chemical structures, thermal properties, hydrogen bonding interactions, and sequence distributions of these random copolymers. Because the reactivity ratio of MMA and HPMI is very different from that of MMA and maleic anhydride (MA), which prefer to form homopolymers, here we obtained partially alternating copolymers featuring strong intermolecular hydrogen bonding between the PMMA and PHPMI segments, resulting in the value of Tg increasing by up to 90 °C relative to that of the pure PMMA homopolymer. In addition, solid state NMR spectra revealed single values for the proton spin–lattice relaxation time in the rotating frame [T1ρ(H)] over all compositions of these random copolymers, with the relaxation times being shorter than the predicted average, indicating that the free volume had decreased and that the copolymers possessed rigid structures with high values of Tg.

Fabrication of TiO2 nanodot films using simple solution dipping method and block copolymer template

Block copolymer (BCP) self-assembled nanostructures as a template in conjunction with a low-cost inorganic material deposition method can be a practical solution for many applications in the fields of microelectronics, optoelectronics, and plasmonics. Here, we demonstrate the fabrication of TiO2 nanodot films using polystyrene-b-polymethylmethacrylate (PS-b-PMMA) BCP as a template and a simple solution dipping process for TiO2 deposition. For this purpose, we prepared BCP templates using two different methods, namely, the selective deposition method and the masked deposition method. In the selective deposition method, as-grown self-assembled cylinder forming PS-b-PMMA was used as a template and in the masked deposition method, PMMA was etched out selectively from PS-b-PMMA nanostructured films. The scanning electron microscopy results show the average diameter of TiO2 nanodots grown by the selective deposition method is smaller compared to the masked deposition method, whereas the inter-nanodot distance is similar for both deposition methods. X-ray diffraction and photoluminescence confirm the formation of TiO2 in samples deposited by these two methods. The smaller nanodot size for the selective deposition method can be attributed to the limited interaction of the Ti precursor used here with the PMMA copolymer active functional groups. Therefore, in addition to being advantageous due to less processing steps, the selective deposition method can be used for the fabrication of lower dimensional nanostructures by identifying proper precursors and polymers and by controlling the interaction parameters. Our results will be useful for exploring interactions of other polymers with inorganic material precursors and thereby fabricating different nanostructures with desired morphologies using a simple and cost-effective dipping method.

Radical reaction extrusion copolymerization mechanism of MMA and N-phenylmaleimide and properties of products.

Using the method of bulk reactive extrusion radical copolymerization, N-phenyl maleimide (N-PMI) and styrene (St) and methyl methacrylate (MMA) were copolymerized. Through multi-detection gel permeation chromatography, bulk copolymerization kinetic analysis, UV-Vis spectroscopy, elemental analysis, and 1H NMR and 13C NMR analysis, it was found that, contrary to the classical free radical copolymerization theory, N-PMI and MMA could not only achieve copolymerization, but could even reach the level of azeotropic copolymerization. The factor that caused this change turned out to be the viscosity of the system. Secondly, through DSC, TG and GC-MS analysis, it was found that N-PMI units were randomly inserted into the molecular chain of PMMA, which greatly improved the stiffness of its molecular segments and the Tg of the copolymer; at the same time, the insertion of N-PMI units also very effectively blocked the zipper-style de-end group degradation that often occurs in PMMA. When the mass content of the N-PMI copolymer reached 10%, the Tg, initial degradation temperature and semi-degradation temperature of the copolymer increased by 19 °C, 58 °C and 47 °C, respectively. In addition, St, N-PMI can also significantly improve the processing fluidity of the PMMA copolymer, and after St participates were introduced in the copolymerization, the melt flow rate can be increased by 3.5 times. Furthermore, the copolymer not only had good mechanical properties and transparency, but also had excellent antibacterial properties against E. coli and S. aureus with only the effect of trace residual N-PMI in the copolymer. This provides an excellent reference for the preparation of antibacterial PMMA with high heat resistance, good mechanical properties and high transparency.

Application of solubility parameters in the preparation of PMMA with permanent antistatic, high toughness, and excellent optical properties

AbstractIn this paper, a novel kind of PMMA copolymer, P(MMA‐co‐MAA‐co‐SPMA), with permanently antistatic, high toughness, and high transparent properties, was synthesized via radical copolymerization. Herein, we selected the appropriate compatibilizer α‐methacrylic acid (MAA) and release agent (lauryldiethanolamine) through the calculation of solubility parameters for industrial mass production. What is more, the polymer's molecular weight was increased by improving the polymer's synthesis process. The structure and properties of the obtained copolymer were characterized. With 0.6 wt% of the 3‐sulfopropyl methacrylate potassium salt (SPMA), the copolymer exhibits nearly unchanged transparency with neat PMMA, and its unnotched impact strength reaches 16 kJ/m2. The surface resistance of the copolymer could be reduced to 1010 Ω, which could be considered as antistatic materials. Finally, the antistatic mechanism was analyzed. The main reason is that the hydrophilic group absorbs water to form a conductive layer on the surface, and 3‐sulfopropyl methacrylate potassium salt (SPMA) is an ionic monomer that can form ion channels in water molecules, further accelerating the leakage of accumulated electrostatic charges and improving the antistatic properties of the copolymer. The method of selecting compatibilizers and release agents through solubility parameters provides more opportunities for the development of PMMA with excellent comprehensive performance.

Crosslinked network formation beyond graft copolymers in transparent bisphenol-A Polycarbonate/Poly(methyl methacrylate) blends catalyzed by bis(trifluoromethanesulphonyl)imide based organic salts

It has been widely accepted that the promoted transparency of bisphenol-A Polycarbonate/Poly(methyl methacrylate) (PC/PMMA) blends was attributed to the transesterification induced PC-graft(g)-PMMA copolymer formation during melt extrusion of the blends. However, prior studies fall short of detailed characterization of the PC-g-PMMA copolymers. In this paper, we investigated the effect of different bis(trifluoromethanesulphonyl)imide-based salts on the compatibilization and optical transparency properties of PC/PMMA blends. It was found that Mg(TFSI)2 showed the best compatibilization effect and could enable transparent blend films for PC/PMMA blends at all PMMA compositions as manifested from scanning electron microscopy (SEM) images, differential scanning calorimetry(DSC) and thermogravimetric analysis(TGA). Moreover, elution experiments with mutual solvent left intractable portion indication crosslinked network formation beyond PC-g-PMMA copolymers. Finally, the detailed structure of PC-g-PMMA copolymers was studied by Gel Permeation Chromatography (GPC). To the best of our knowledge, this is the first time to analyze the detailed structure of the PC-g-PMMA copolymers formed during melt extrusion.

Reduction of Magnesium Corrosion Rate by PMMA-co-PMAA Films

Magnesium is an important base material for non-permanent implants, even though its corrosion rate in the human body is usually elevated for most applications. In order to reduce that rate, polymer coatings can be a better option than heavy-metal containing Mg alloys. In this work, random copolymers of PMMA and PMAA were synthesized and used for coating pure Mg by simply immersing Mg coupons into a diluted copolymer solution. It has been shown by SEM analysis and quantitative adsorption analysis that the copolymers have adsorbed onto the Mg surface. All the coated materials presented a lower corrosion rate than the uncoated Mg, reaching close to 100% reduction for most of the copolymer up to 6 hours of testing. The copolymers with 5, 8 and 13% of PMAA in their composition showed the best performances as corrosion controllers.

The preparation and mechanism of permanently flame retardancy, antistatic, good toughness and high transparent poly(methyl methacrylate)

AbstractA novel kind of poly(methyl methacrylate) (PMMA) copolymer, P(MMA‐co‐HEMAP), with permanently flame retardancy, antistatic, good toughness and high transparency properties was synthesized through the addition of 2‐hydroxyethyl 2‐methyl‐2‐propenoate phosphated (HEMAP), which was chosen as the flame retardant and the antistatic agent. The included phosphine group is necessary for flame retardancy and acryl phosphate group that could absorb water to realize antistatic property while having good compatibility with methyl methacrylate (MMA). Different from the significantly reduction of transparency happened in traditional modification method, the optical property of the P(MMA‐co‐HEMAP) copolymers keeps almost unchanged comparing to that of neat PMMA in the visible range. And the peak Heat Release Rate (pHRR) and Total Heat Release (THR) of the 30PhrHEMAP were significantly reduced by 40% and 36.2%, respectively, while the Limiting Oxygen Index (LOI) increased from 17.8 to 24.5%. The HEMAP decomposed during the combustion process to form polyphosphoric acid, which promotes dehydration and carbonization of polymer matrix to form a cross‐linking yield char and it would reduce fire spread. Besides, the surface resistance of the 30PhrHEMAP could be reduced down to 1010Ω which could achieve antistatic effect. The hydrophilic groups, acryl phosphate on the surface of copolymer was able to absorb moisture from the air for antistatic effects. Furthermore, the toughness of the copolymers was also greatly improved compared to that of neat PMMA. This research provided a method for preparing PMMA copolymer and the resultant P(MMA‐co‐HEMAP) copolymers can significantly improve the three properties simultaneously for the first time.

Improvement of PLLA Ductility by Blending with PVDF: Localization of Compatibilizers at Interface and Its Glycidyl Methacrylate Content Dependency.

In this work, the localization of reactive compatibilizer (RC, containing poly(methyl methacrylate) (PMMA) backbone with randomly distributed glycidyl methacrylate (GMA) on it) at the polyvinylidene fluoride/poly(l-lactic acid) (PVDF/PLLA) interface has been manipulated by means of GMA contents. At the very beginning of mixing, RC tends to stay in the PVDF phase due to the miscibility between PVDF and PMMA. Upon further shearing, more and more PLLA chains have been grafted on PMMA backbone, producing PLLA–g–PMMA copolymer. The balanced stress on two sides accounts for the localization of compatibilizers at the PVDF/PLLA interface. Finally, the stress of the PLLA side has been enhanced remarkably due to the higher graft density of PLLA, resulting in the enrichment of the copolymer in the PLLA matrix. The migration of RC from the PVDF phase to the immiscible interface and PLLA matrix can be accelerated by employing RC with higher GMA content. Furthermore, the compatibilizer localization produces a significant influence on the morphology and ductility of the PVDF/PLLA blend. Only when the compatibilizers precisely localize at the interface, the blend exhibits the smallest domain and highest elongation at break. Our results are of great significance for not only the fabrication of PLLA with high ductility, but also the precise localization of compatibilizers at the interface of the immiscible blend.

Converting Poly(Methyl Methacrylate) into a Triple-Responsive Polymer.

Multiresponsive polymers that can respond to several external stimuli are promising materials for a manifold of applications. Herein, a facile method for the synthesis of triple‐responsive (pH, temperature, CO2) poly(N,N‐diethylaminoethyl methacrylamide) by a post‐polymerization amidation of poly(methyl methacrylate) (PMMA) is presented. Combined with trivalent counterions ([Fe(CN)6]3−) both an upper and lower critical solution temperature (UCST/LCST)‐type phase behavior can be realized at pH 8 and 9. PMMA and PMMA‐based block copolymers are readily accessible by living anionic and controlled radical polymerization techniques, which opens access to various responsive polymer architectures based on the developed functionalization method. This method can also be applied on melt‐processed bulk PMMA samples to introduce functional, responsive moieties at the PMMA surface.

Synthesis of a novel phosphate‐containing highly transparent PMMA copolymer with enhanced thermal and flame retardant properties

A novel poly(methyl methacrylate) (PMMA)‐based copolymer (PMMA‐co‐BDPA) rich in aromatic rings was synthesized via radical copolymerization between a phosphorus‐containing acrylic monomer (BDPA) and methyl methacrylate (MMA). UV‐vis spectroscopy demonstrated that the copolymer had high transparency. Thermogravimetric analysis (TGA) and a differential scanning calorimeter (DSC) were used to test the thermal properties of the composites. Additionally, the PMMA‐co‐BDPA‐15 copolymer exhibited a 23% increase in the limited oxygen index (LOI) value. A cone calorimeter test indicated that the peak heat release rate (pk‐HRR) of PMMA‐co‐BDPA was reduced by 29.2% compared with that of pure PMMA, and the carbon yield of burning was obviously increased. The combined test results demonstrated that the prepared copolymer material had good transparency, thermal stability, and flame retardancy.

X-ray characterization of crosslinked methacrylate copolymers for application as dielectric layers in organic electronics

Poly(methyl methacrylate) (PMMA) is one of the most important polymers for application as a dielectric layer in organic electronics, e.g. in organic field-effect transistors. The key to improve the transistor performance is the optimization of the interface between the semiconductor and the dielectric layer. Here, the surface order in thin films of PMMA copolymers with self-organized, semifluorinated (sf) building blocks, and crosslinkable units in single layers and double layers with poly(3-hexylthiophene-2,5-diyl) (P3HT) is investigated. The chemistry of the sf copolymers is systematically varied and the influence on the self-organization in bulk and thin films is examined by a combination of scattering methods. The length of the semifluorinated side chains mainly determines the degree and type of order both in bulk as well as in thin films.

Synthesis of acrylic hot-melt adhesive based on poly(methyl methacrylate)-b-poly(2-ethylhexyl acrylate) copolymer using atom transfer radical polymerization for a nylon fabric bonding system

Adhesives, such as hot-melt adhesives (HMAs), are widely used in the textile industry for bonding layers of materials and have replaced traditional sewing methods. The block copolymer is a common type of HMA that provides excellent physical features and mechanical properties compared with others. Acrylate-based monomers, methyl methacrylate (MMA), and 2-ethylhexyl acrylate (2-EHA) were used as ingredients to form a linear block copolymer using atom transfer radical polymerization. MMA provides excellent cohesive strength, while 2-EHA provides good adhesion properties. An end-brominated poly(methyl methacrylate) (PMMA-Br) macroinitiator was synthesized from a MMA monomer and initiator, with the best composition obtained by the addition of a 0.6 mol initiator. The macroinitiator had the lowest molecular weight with highest conversion (97%). The addition of a 0.3 mol macroinitiator showed the lowest molecular weight with the highest conversion of acrylic copolymer PMMA- b-poly(2-ethylhexyl acrylate) (PEHA). The glass transition temperature increased with the addition of the macroinitiator concentration, from −43.7℃ to −37.6℃. The thermal stability was reduced with the addition of macroinitiator content, from 332.37℃ to 286.81℃. The shear strength and peel strength of the PMMA- b-PEHA HMAs on nylon fabrics were enhanced from 11.24 to 16.92 kg cm−2 and from 0.29 to 0.61 kg cm−1, respectively, and did not change significantly after being washed 50 times and then kept in low-temperature storage, with the addition of the macroinitiator concentration. The block copolymer PMMA- b-PEHA prepared in this study could be used as a HMA for nylon fabric bonding systems.

Irreversible Physisorption of PS-b-PMMA Copolymers on Substrates for Balanced Interfacial Interactions as a Versatile Surface Modification.

We present a direct approach to fabricating the perfect neutral layer for block copolymer (BCP) self-assembled thin films. An irreversible physisorption of polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) itself onto the bottom substrates, though extremely thin, offers such a compositional randomness for the substrates, directing the balanced interfacial interactions toward both blocks of the top-layer PS-b-PMMA. Owing to the neutral property from the skin layers, the chemically identical BCP self-assembles into perpendicular microdomains on the adsorbed layer composed of itself, as identified in symmetric PS-b-PMMA films. Intriguingly, the compositional randomness turns out to be valid when the correlation length (ξ) of the BCP layer adsorbed on the substrates is shorter than equilibrium lamellar spacing (L0) of the BCP. Our strategy provides its versatility applicable to various substrates without any necessity of specific random copolymer brushes or mats, enabling the design of a neutral platform for PS-b-PMMA films.

Efficient preparation and characterization of paraffin‐based microcapsules by emulsion polymerization

ABSTRACTMicroencapsulated phase‐change materials (MEPCMs) with paraffin as the core and poly(methyl methacrylate) (PMMA) and PMMA copolymers as the shell were prepared by emulsion polymerization using redox initiators at low temperatures. Fourier transform infrared spectroscopy was used to characterize the chemical composition of MEPCMs. The thermal properties and thermal stabilities of MEPCMs were tested by differential scanning calorimetry and thermogravimetric analysis. The morphologies and sizes of the microcapsules were investigated by scanning electron microscopy and particle size distribution analysis. The results indicated that the yield of microcapsules is as high as 96.2%, and the encapsulation efficiency of paraffin is nearly 100% when the paraffin content in MEPCM is 70%. The MEPCMs have good stability: the leakage ratios of MEPCMs can be less than 1% after 50 heating–cooling cycles. Therefore, the microencapsulation of paraffin using redox initiators has good production and application prospects. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47552.