Copolymerization Of Methyl Methacrylate Research Articles

Highly‐modified polylactide transparent blends with better heat‐resistance, melt strength, toughness and stiffness balance due to the compatibilization and chain extender effects of methacrylate‐co‐glycidyl methacrylate copolymer

AbstractA core‐shell modifier with the cross‐linked acrylate and silicone copolymer as the core and polymethyl methacrylate (PMMA) as the shell (PASi‐g‐PMMA) was used to toughen the brittle polylactide (PLA). In addition, the copolymer of methyl methacrylate (MMA) and glycidyl methacrylate (GMA) (MG) was utilized to further enhance the modification efficiency of the PASi‐g‐PMMA. The MG copolymer played the double roles of compatibilizer and chain extender, which not only improved the interfacial adhesion between the PLA and PASi‐g‐PMMA particles, but also increased the molecular weight and chain entanglement of the PLA. Compared with the PASi‐g‐PMMA toughened PLA blend, the PLA/PASi‐g‐PMMA/MG blends showed much higher heat‐resistance, melt strength, transparency, toughness and stiffness balance. When the PASi‐g‐PMMA content was 20 wt%, 20 wt% MG increased the glass transition temperature (Tg), complex viscosity (η*), transparency, impact and tensile strength of PLA/PASi‐g‐PMMA blend from 60.1°C, 1.9 × 103 Pa·s, 76.1%, 748 J/m and 37 MPa to 71.5°C, 0.5 × 104 Pa·s, 78.4%, 860 J/m and 45 MPa for the PLA/PASi‐g‐PMMA/MG blend. This research provided a facile and practical method to overcome the shortcomings of the PLA and promoted its application in broader fields.

Experimental studies on static laser light scattering of synthetized poly (acrylonitrile-co- methyl methacrylate) copolymer at room temperature

The static light scattering technique (SLS) is one of the absolute techniques that are used for the determination of weight average molecular weight (M¯w) of polymer solutions. In this technique, the scattered laser light intensity is measured at different scattering angles for various polymer concentrations to construct the Zimm plot which can be used for a simultaneous determination of M¯w, radius of gyration (Rg), and the second virial coefficient (A2). In this study, Poly (acrylonitrile–co-methyl methacrylate) copolymer, P(AN-co-MAA), was synthesized from acrylonitrile (AN) and methyl methacrylate (MMA) monomers using the precipitation polymerization method. Polymerization was carried out using potassium persulfate (K2S2O8) as an initiator with monomer ratios 1:1 of AN: MMA. The co-polymerization process was verified by Fourier transform infrared spectroscopy (FTIR). Refractive index (n) and refractive index increment (dn/dc) of the P(AN-co-MAA) copolymer solutions were determined experimentally using a Mach-Zehnder interferometer excited by a low power He-Ne laser in order to calculate the M¯w, Rg, and A2 of the synthetized copolymer using the static laser light scattering technique. M¯w, Rg, and A2 were found to be 9.7 × 105 g/mol, 345 nm, and 5 × 10−7 mol. cm3/g2.

Graft copolymerization of methyl methacrylate on Meizotropis Pellita fibres and their applications in oil absorbency

This research paper deals with the graft copolymerisation of methyl methacrylate (MMA) on the backbone of Meizotropis Pellita fibres (MPF), which was successfully carried out under aqueous medium using Fenton's reagent [ferrous ammonium sulphate (FAS) (8.0 × 10–3 M) and H2O2 (0.12 M)] as a redox initiator to impart hydrophobic properties. Grafting was optimized under different conditions concerning time, temperature, monomer ratio, material to liquor ratio and initiator concentration. Maximum graft yield percentage obtained was 120%. The grafted MPF was characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and X-ray diffraction (XRD) studies. The FTIR spectroscopic data showed a peak at 1728 cm−1 of C=O (ester), and another peak at 1650 cm−1 of adsorbed water, which was absent in the grafted fibre. The grafted fibre showed excellent thermal stability with an overall weight loss of 56.5% with a char residue of 33.5%. In addition, X-ray diffraction of MMA-grafted MPF showed 21% crystallinity and crystallinity index of 0.16. These raw and grafted fibres were also subjected to physico-chemical properties like moisture absorbance, swelling behaviour and chemical resistance, which they showed that MMA-grafted MPF exhibited hydrophobic properties. Therefore, due to this hydrophobic behaviour, the oil absorbency of MMA-grafted MPF was studied towards four emulsions: crude oil–saline, engine oil–saline, diesel oil–saline and used engine oil–saline. An MMA-grafted MPF by 120% absorbed 23.60 g of crude oil in the first cycle, 17. 41 g in the second cycle and 14.21 g in the third cycle, whereas 13.14 g of diesel oil was absorbed in the first cycle, 8.24 g in the second cycle and 5.25 g in the third cycle. Similarly, 20.14 g of engine oil was absorbed in the first cycle, 10.00 g in the second cycle and 7.51 g in the third cycle. Lastly, 19.80 g of the engine oil was absorbed in the first cycle, 12.25 g in the second cycle and 7.98 g in the third cycle. These results showed that the oil removal efficiency of the grafted MPF was intact by oil fraction type and they can be applied for all kinds of oil fraction spillage.

Transpicuous-Cum-Fouling Resistant Copolymers of 3-Sulfopropyl Methacrylate and Methyl Methacrylate for Optronics Applications in Aquatic Medium and Healthcare

The scope of optical sensors and scanners in aquatic media, fluids, and medical diagnostics has been limited by paucity of transparent shielding materials with antifouling potential. In this research endeavor, facile synthesis, characterization, and bioassay of antifouling transparent functional copolymers are reported. Copolymers of 3-sulfopropyl methacrylate (SPMA) and methyl methacrylate (MMA) were synthesized by free radical polymerization in various proportions. Samples PSM20, PSM30, PSM40, PSM50, and PSM60 contain 20%, 30%, 40%, 50%, and 60% SPMA by weight, respectively. Resultant products were characterized by FTIR and 1H-NMR spectroscopy. The synthesized copolymers have exhibited excellent transparency, i.e., 75% to 88%, as determined by the UV-Vis spectroscopic analysis. Transmittance was decreased from 6% to 2% in these copolymers upon changing the concentration of 3-sulfopropyl methacrylate from 20% to 50% owing to bacterial and algal biofilm formation. Water contact angle values were ranged from 18° to 63° and decreased with the increase in the polarity of copolymers. The surface energy lowest value 58 mJ/m2 and highest value 72 mJ/m2 were calculated for PSM20 and PSM50, respectively, by the Chibowski approach and Young equation. Sample PSM50 has exhibited the highest antibacterial activities, i.e., 18 mm and 19 mm, against Escherichia coli and Staphylococcus aureus, respectively, by the disk diffusion method. Copolymer PSM50 has shown minimum algal adhesion for Dictyosphaerium algae as observed by optical microscopy. This lower bacterial and algal adhesion is attributed to higher concentrations of anionic SPMA monomer that cause electrostatic repulsion between functional groups of the polymer and microorganisms. Thus, the resultant PSM50 product has exhibited good potential for optronics shielding application in aquatic medium and medical diagnostics.

Synthesis and characterization of phase change materials microcapsules with paraffin core/cross-linked hybrid polymer shell for thermal energy storage

Phase change materials microcapsules (PCMM) with cross-linked hybrid polymer shell were developed by in-situ polymerization and paraffin melting at 47 °C was used as PCM. The cross-linked hybrid polymer shell of microcapsules was prepared by copolymerizing methyl methacrylate (MMA), acrylic acid (AA), n‑butyl acrylate (BA), and trimethylpropane triacrylatec (TMPTA) which were employed as crosslinking agents. Microcapsules with core–shell structure were studied by polarizing optical microscope (POM), and their morphologies were obtained by scanning electronic microscope (SEM). Fourier transform infrared (FR-IR) was used to characterize the PCMM with paraffin core. The results of differential scanning calorimetry (DSC) showed that the measured enthalpy of PCMM was significantly higher than the theoretical value, and the increment percentage was as high as 58.7% and 63.9% during the heating/cooling process, respectively. In addition, PCMM's good thermal stability and long-term property were obtained by thermogravimetric analysis (TGA) and thermal cycle test results.

Study of poly(organic palygorskite‐methyl methacrylate)/poly(ethylene oxide) blended gel polymer electrolyte for lithium‐ion batteries

AbstractIn this study, the composite polymer was prepared by blending poly(ethylene oxide) (PEO) and POPM (the copolymer of methyl methacrylate [MMA] and organically modified palygorskite), and then the composite polymer based membrane was obtained by phase‐inversion method. The scanning electron microscopy results showed that the composite polymer membrane has a three‐dimensional network structure. X‐ray diffraction results indicated that the crystalline region of PEO is disappeared when introduction of a certain amount of the PEO. Meanwhile, the elongation of composite polymer membrane increased when increasing PEO concentration, but the value of tensile strength of PEO‐POPM membrane decreased. When the mass fraction of PEO was 24%, the porosity and maximum value of ionic conductivity of the composite polymer membrane were 54% and 2.41 mS/cm, respectively. The electrochemical stability window of Li/gel composite polymer electrolyte/stainless steel batteries was close to 5.3 V (vs. Li+/Li), and the battery of Li/gel composite polymer electrolyte/LiFePO4 showed good cycling performance and the discharge capacity of the battery were between 169.8 and 155 mAh/g. Meanwhile, the Coulombic efficiency of the battery maintained over 95% during the 80 cycles.

Methyl methacrylate-styrene copolymers prepared by utilizing the Trommsdorff effect in an inverted two-stage extruder

In this work, the influence of initial viscosity on the Trommsdorff effect was firstly investigated, and it was confirmed that 1000 ± 100 Pa · s of viscosity could be a criterion of the Trommsdorff effect. On this basis, a new inverted two-stage extruder was established, the designed ‘blocking unit’ was introduced to the screw configuration, and then the continuous bulk copolymerization of methyl methacrylate (MMA) and styrene (St) was carried out. The results showed that the blocking unit could effectively enhance the residence time of copolymerization, and make the molecular weight distribution of copolymer more uniform. The position of the Trommsdorff effect in the extruder was then determined by the thermal effect of copolymerization, and the mixed monomers were continuously added to effectively utilize the Trommsdorff effect. As a result, the MMA-St copolymers with high molecular weight and narrow distribution were prepared via reactive extrusion, which possessed higher melt flow rate and better thermal stability than pure-PMMA. The present work provides important reference and guidance for the industrialization of bulk free radical copolymerization via reactive extrusion.

Highly oriented ferromagnetic polymers based on Co- and Fe-rich amorphous microwires

In this paper highly oriented magneto-polymer composites have been obtained by means of Co and Fe-rich glass-coated amorphous microwires with various metal nucleus and outer diameters. The microwire segments with length L ~ 0.5–0.6 cm were oriented in the magnesium alloy matrix and were poured with a liquid polymer whose composition was a mixture of methyl methacrylate methacrylic acid and methacrylate copolymers in a ratio of 37/63% by mass. The magneto-polymer composites obtained possess high electric resistance, chemical stability and mechanical strength. The high average saturation magnetizations, <Ms> = 20–30 emu/cm3, have been obtained for Co and Fe based composites with the volume fraction of the magnetic material in the polymer matrix within the range 0.02–0.05. Both Co and Fe based composites show highly anisotropic magnetic properties. The magneto-polymer samples can be cut into pieces of arbitrary size and shape. This facilitates their use in various technical applications.

Foaming behavior of 1-vinyl-2-pyrrolidone–methyl methacrylate copolymers under ScCO2

We report on the preparation, characterization, and foaming behavior of cellular polymers based on 1-vinyl-2-pyrrolidone (VP) and methyl methacrylate (MMA). Samples with different feed ratios proportions of VP and MMA were prepared following the bulk radical copolymerization procedure, using commercially available monomers and testing two different initiators (photochemical and thermal), obtaining solid samples of around 1.5 mm thick. To evaluate the polymerization process, the chemical structure of VP/MMA copolymers was determined by proton nuclear magnetic resonance measurements. In a second step, single-batch supercritical carbon dioxide (CO2) foaming tests were carried out at different temperatures to evaluate the influence of the VP to MMA feed ratios and the foaming temperature in the density, the presence of solid outer skin, the CO2 sorption–desorption process, and the cellular morphology of the foamed polymers.

Polymer side-chain modification in methacrylate and styrene copolymers through thiol-thioester dynamic exchange

In this paper a methacrylic derivative of naphthalene-2-thiol – S-naphthalene-2-yl 2-methylprop-2-enethioate (2-NAF-S-Met) was synthesized and then copolymerized with two monomers of industrial significance, i.e. methyl methacrylate (MMA) and styrene (ST). The thermal properties of the copolymers were investigated by differential scanning calorimetry (DSC) and thermogravimetry (TG/DTG). Also, Shore hardness tests of the obtained polymers and optical properties (transparency) were assessed. By replacing the thioester-linked substituent components of the side chains in the thioester-derived polymers through the thiol-thioester exchange reactions, a facile control over the polymer properties (hardness, Mn and Mw, transparency, stability, solubility, etc.) was demonstrated. The molar masses (Mn) of new materials after thiol-thioester exchange using 2-mercaptoethanol were reduced to 6.85 × 104 Da (for ST copolymers) and to 1.22 × 106 Da (for MMA copolymers), respectively. Second exchange sequence with thiophenol resulted in an increase in the molar mass of these products. The replacement of substituents also caused an improvement in thermal stability, especially for MMA copolymers, as well as a decrease of the glass transition temperatures.

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.

On Particle Size Distributions in Catalytic Chain Transfer Emulsion Polymerization: Chain-Extension and the Use of Derived Macromonomers as Reactive Surfactants in Emulsion Polymerization.

Catalytic chain transfer emulsion polymerization (CCTP) and subsequent chain extension via reversible addition-fragmentation chain transfer (RAFT) were used to synthesize amphiphilic macromonomers (MM), in the form of polymer latexes. The macromonomers consisted of two blocks whose first was a random copolymer of methacrylic acid and methyl methacrylate, at 35:65 mol:mol, while the second block was n-butyl methacrylate P[(MAA-co-MMA)-block-PBMA]. The block copolymer colloids were disintegrated and micellized upon addition of ammonia. The resulting nanosized polymer dispersions were used as reactive surfactants in the emulsion polymerization of n-butyl methacrylate. For this, a dual stage slow-fast monomer feed profile was used. The final polymer latexes were in the sub-100 nm range for the particle diameter at 30% w/w total polymer content. The emphasis of the work is to discuss and find an explanation for the observed particle size distributions in the three consecutive emulsion polymerization steps. The particle size distribution of the ω-unsaturated macromonomer latex synthesized by CCTP emulsion polymerization was found to be much broader than expected. This discrepancy is attributed to an extended particle nucleation period. The chain extension step in the macromonomer latex preparation showed considerable secondary nucleation. The presence of water-soluble macromonomer species from the CCTP emulsion polymerization step assured that control of chain growth persisted. The use of the amphiphilic macromonomers as reactive surfactants in the form of a nanosized aggregate seed dispersion showed that the average particle diameter could be tuned and that the molecular weight distributions could be regulated, when monomer starved conditions were used in the emulsion polymerizations.

Improvement of Thermal and Mechanical Properties of Vietnam Deproteinized Natural Rubber via Graft Copolymerization with Methyl Methacrylate

In this study, we investigated the improvement of the thermal and mechanical properties of Vietnam deproteinized natural rubber (DPNR) via graft copolymerization of methyl methacrylate (MMA). The graft copolymerization was achieved successfully in latex stage using tert-butyl hydroperoxide (TBHPO) and tetra-ethylenepentamine (TEPA) as radical initiators at 30°C. By grafting with various MMA feeds and initiator concentration of 6.6×10−5 mol/g-rubber, the highest grafting efficiency and conversion were achieved at MMA of 15 wt.% per kg of rubber, 68% and 90%, respectively. The structure of grafted copolymers was characterized by 1H NMR, FTIR-ATR, and GPC, and thermal properties were investigated through DSC and TGA measurements. These showed that graft copolymers were more stable and rigid than DPNR. Storage modulus (G′) of graft copolymer was found to double that of DPNR, which contributed to the formation of graft copolymer. After sulfur vulcanization, the mechanical properties of DPNR-graft-PMMA, such as tensile strength, tear strength, and hardness, were improved significantly. Curing behaviors of the graft copolymers were found to be remarkably better than virgin DPNR.

Graft copolymerization of methyl methacrylate on Abelmoschus manihot fibres and their application in oil absorbency

This paper deals with the graft copolymerization of methyl methacrylate (MMA) on the backbone of Abelmoschus manihot fibres (AMF) successfully carried out under aqueous medium using Fenton's reagent [(ferrous ammonium sulphate (FAS) (8.0 × 10–3 M) and H2O2 (0.12 M)] as a redox initiator and N,N′-methylene bisacrylamide as a crosslinker to impart hydrophobic properties. Grafting was optimized under different conditions concerning time, temperature, monomer ratio, material to liquor ratio, initiator concentration. Maximum graft add-on% obtained was 130% at a temperature of 75 °C, 3:1 monomer to fibre ratio, time of 150 min, 1:75 fibre to liquor ratio and 20:20 (FAS: H2O2) initiator concentration. The grafted AMF fibres were characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and X-ray diffraction (XRD) studies. FT-IR spectroscopic data showed a peak at 1726 cm−1 of C=O (ester), and another peak at 1650 cm−1 of adsorbed water was absent in the grafted fibre. The grafted fibre showed excellent thermal stability with an overall weight loss of 51.8% and char residue of 48.2% as well as X-ray diffraction of MMA grafted AMF showed 23% crystallinity and crystallinity index of 0.19. These raw and grafted fibres also subjected to physico-chemical properties like moisture absorbance, swelling behaviour and chemical resistance studies showed that MMA grafted AMF exhibited hydrophobic properties. Therefore, due to this hydrophobic behaviour, the oil absorbency of MMA grafted AMF was studied towards four emulsions: crude oil saline, engine oil saline, diesel oil saline and used engine oil saline. In total, 130% grafted AMF fibre absorbed 30.07 g of crude oil, 12.20 g of diesel oil, 16.00 g of engine oil and 17.32 g of used engine oil. These results showed that the oil removal efficiency of the grafted AMF was intact by oil fraction type and can be applied for all kinds of oil fraction spillage.

Siloxy Silylester Methacrylate Diblock Copolymer-Based Coatings with Tunable Erosion and Marine Antifouling Properties

pMATM2-b-p(MMA-co-BMA) diblock copolymers composed of a block of poly[bis(trimethylsiloxy)methylsilyl methacrylate] (MATM2) and a second block of a random copolymer of methyl methacrylate (MMA) and...

Multi-layer dressing made of laminated electrospun nanowebs and cellulose-based adhesive for comprehensive wound care

In this work, multi-layer wound dressing was made of laminated layers of electrospun fibers supported by adhesive sheet. Graft copolymerization of methyl methacrylate (MMA) and 2-Ethyl-1-hexyl acrylate (EHA) onto carboxymethyl cellulose (CMC) was conducted to obtain an adhesive sheet with 1.52 (N/cm2) loop tack, 1.7 (N/cm) peel strength and 25 s shear strength. Diclofenac sodium, anti-inflammatory drug, was loaded to the adhesive sheet with encapsulation efficiency 73%.The contact layer to wound was made of synthesized anti-bleeding agents, chitosan iodoacetamide (CI) loaded into electrospun polyvinyl alcohol (PVA) fibers. It was fabricated from fiber diameter 300 nm by electrospinning of 5% wt/v of CI (D.S. 18.7%) mixed with 10% wt/v PVA, at 20 kV and 17 cm airgap. The second, pain-relief layer was fabricated by encapsulating up to 50% wt/wt of capsaicin into gelatin nanofibers (197 nm) crosslinked by glyoxal. The third, antimicrobial layer was fabricated from PVA electrospun fibers loaded with 2% wt/wt gentamicin. Biocompatibility test showed insignificant adverse effects of the fabricated layers on fibroblast cells. Animal test on rat showed accelerated wound healing from 21 to 7 days for the multi-layer dressing. Histopathological findings corroborated the intactness of the epidermis layer of the treated samples.

Reversible inhibition in the formation of copolymers based on alkyl (meth)acrylates with vinyl butyl ethers under compensation of the active monomer depending on their nature when initiated by the triethylborane–oxygen system

Compensatory (or compensation) copolymerization of alkyl (meth)acrylates (AMA) with boiling vinyl butyl ether (VBE), initiated by the system of triethylborane (TEB)–oxygen, has been studied. The obtained data indicate a partial formation of copolymer macromolecules with close to an alternating structure, according to the reversible inhibition mechanism, along with a copolymer formation on the scheme of conventional bimolecular termination. Specific features of used acrylic monomers have been revealed. Copolymers of methyl methacrylate (MMA) and VBE were applied as macroinitiators for block-copolymer syntheses when adding new portions of butyl acrylate (BA).

Reversible polystyrene-block-poly(methyl methacrylate) copolymer films with perpendicular orientation by ultra-thin polystyrene substrates

Detecting the inner structures in the perpendicularly orientated block copolymer (BCP) films is beneficial to understand the in-depth arrangement of nano-domains. This study presents a method to reverse the perpendicularly orientated polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) BCP films for observing their bottom morphologies. Only PS brush or mat was used as neutral substrates, because strongly polar groups inside the PS chains exposed to balance the interfacial energies of PS-OH chemical substrates. The perpendicular window for fingerprint morphology of PS-b-PMMA BCP was among 1.16∼1.44 nm of PS brush on silicon wafer with silanol group. For crosslinked PS mat on water soluble substrate of sodium polyacrylate, however, perpendicular window was shortened to be around 1.37 nm, which was confirmed by both interfacial energy and images of scanning electron microscope (SEM). The bottom views of PS-b-PMMA block copolymer films with perpendicular and mixed orientation were observed freshly. There was no obvious difference between the fingerprints of top and bottom, indicating that perpendicular orientation in the block copolymer was through the film up to down. Therefore, the challenges of degrees of perfection from directed assembly of various morphologies are deduced to be originated from match of the morphology with the e-beamed prepattern or defects in the prepattern.

Controlled Synthesis of Poly(pentafluorostyrene-ran-methyl methacrylate) Copolymers by Nitroxide Mediated Polymerization and Their Use as Dielectric Layers in Organic Thin-film Transistors.

A library of statistically random pentafluorostyrene (PFS) and methyl methacrylate (MMA) copolymers with narrow molecular weight distributions was produced, using nitroxide mediated polymerization (NMP) to study the effect of polymer composition on the performance of bottom-gate top-contact organic thin-film transistors, when utilized as the dielectric medium. Contact angle measurements confirmed the ability to tune the surface properties of copolymer thin films through variation of its PFS/MMA composition, while impedance spectroscopy determined the effect of this variation on dielectric properties. Bottom-gate, top-contact copper phthalocyanine (CuPc) based organic thin-film transistors were fabricated using the random copolymers as a dielectric layer. We found that increasing the PFS content led to increased field-effect mobility, until a point after which the CuPc no longer adhered to the polymer dielectric.

Photochromism of photopolymerized novel copolymers having spirooxazine moiety groups

A novel class of photochromic copolymer based on spironaphthoxazine (SO) moieties was smoothly prepared through the copolymerization of methyl methacrylate (MMA), butyl acrylate (BA) and SO-based monomer by photopolymerization. Polymerization efficiency was studied by measuring the content of SO in eluents, which decreased with increasing mass ratio of SO in precursor monomer. The incorporated SO moieties endow the copolymers with remarkable photochromic ability. The novelty of this study is that unlike conventional physically blending photochromic polymer, SO moieties were chemically bonded with polymer chain, which is an effective way to prevent the SO from migration, thus increasing the stability and reliability during the long-term application. Moreover, the copolymerization was prepared through UV polymerization in the absence of organic solvent, which is environmentally friendly. Polymer chain flexibility can be well tuned by changing the mass ratio of BA. To make the copolymer more flexible, plasticizer of dibutyl phthalate (DBP) was also introduced. The photochromic ability of the as-prepared films was enhanced with increase in flexibility of polymer chain, which achieved the optimum state when the mass ratios of plasticizer DBP (dibutyl phthalate) and precursor BA (butyl methacrylate) were 20% and 50%, respectively. The thermal stability and tensile strength of the products were characterized by thermogravimetric analysis and electronic universal testing machine, which revealed that these copolymers could be applied as photochromic materials.