Effects of fluorinated substituents on the refractive index and optical radiation resistance of methacrylates

Novel fluorinated methacrylate polymers were synthesized. The purpose was to produce polymers with low refractive indices and increased resistance to optical radiation damage. Six different fluorinated substituents were appended on the monomer before polymerization. Optical-quality samples were prepared, and their transmission spectra, through 0.8 cm thick samples, were obtained. Each sample was tested for refractive index and glass transition temperature. The samples absorbed 10 MRad gamma radiation from a ⁶⁰Co source in an air environment; their transmission spectra were recorded immediately after irradiation and again after seven days had elapsed. As expected, increasing the fluorine content in the side chains resulted in decreased refractive indices. Fluorine content also influenced optical radiation stability. One polymer, poly(1H,1H-heptafluorobutyl methacrylate) retained superior UV/visible transmission after irradiation. © 1993 John Wiley & Sons, Inc.     

Acrylate-based fluorinated copolymers for high-solids coatings

A series of low, medium, and high molecular weight copolymers containing methyl methacrylate, n-butyl acrylate, 2-hydroxyethyl methacrylate, and 2,2,2-trifluoroethyl methacrylate were synthesized by solution polymerization under monomer-starved conditions. The acrylate-based copolymers were characterized by FTIR; ¹H, ¹³C, and ¹⁹F NMR, and MALDI-TOF mass spectrometry. The molecular weights and the glass transition temperatures of the copolymers were determined using Gel Permeation Chromatography (GPC) and Differential Scanning Calorimetry (DSC). The copolymers were crosslinked with a methylated melamine formaldehyde resin in order to obtain thermosetting acrylics. Surface, optical, barrier, mechanical, and viscoelastic properties of the acrylic coatings were investigated. An enrichment of fluorinated units at the acrylic surface was directly verified measuring dynamic contact angles. Lower wettability, higher oxygen permeability, and lower refractive index were observed for higher concentrations of fluorinated monomer in the copolymer composition. High number-average hydroxyl functionality of high molecular weight copolymers increased the crosslink density of the acrylic films, resulting in improved tensile strength and tensile modulus.     

Preparation and properties of methyl methacrylate and fluoroacrylate copolymers for plastic optical fiber cladding

Copolymers of methyl methacrylate (MMA) and fluoroacrylate (FA), with different FA content (0–100 wt %), were prepared by bulk polymerization. The chemical structure was identified by ¹H‐NMR and other physical properties were measured by DSC, Abbé refractometer, X‐ray diffractometry, polarized optical microscopy, and DMA. The copolymers were confirmed as random copolymers by Fineman–Ross analysis and first‐order Markov statistics. Increasing the FA content from 0 to 100 wt % decreased the refractive index from 1.492 to 1.368. Copolymers with FA content higher than 70 wt % crystallized and led to low transparency and poor thermal properties. On the other hand, copolymers with FA content lower than 70 wt % was thermally stable (T_g was as high as 60°C) and transparent. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2082–2089, 2004     

Effects of composition and plastifier on the light scattering of polymer glasses and properties of polymeric optical fibers made from styrene-methyl methacrylate copolymers

High optical purity polystyrene (PS), poly(methyl methacrylate) (PMMA) and styrene-methyl methacrylate statistical copolymers (S-MMA) were prepared. Light scattering measured on polymeric glasses depends on the chemical composition of the polymer and on the refractive index of the plastifier added. An isorefractive plastifier reduces considerably the scattering values for the copolymers S-MMA, while having no significant effect on the scattering of PMMA. A plastifier with a refractive index different from that of the polymer raises distinctly the light scattering values in all cases. It has been shown that the isorefractive plastifier has a favourable effect on attenuation loss of polymeric optical fibers (POF) obtained from the copolymer S-MMA 2/1.     

Transparent chiral polymers for optical applications

Optically active chiral polymers and copolymers of cholesteryl methacrylate have been studied for use in optical applications including plastic optical fibers. Homopolymers of chiral cholesteryl methacrylate with differing molecular weights and copolymers with methyl methacrylate were synthesized by free‐radical copolymerization in tetrahydrofuran using azobisisobutyronitrile at 67°C for 26 h. All polymers were characterized for molecular weight, glass‐transition temperature, optical rotation, transparency, and refractive index and solution blended to test for compatibility with poly(methyl methacrylate). Such chiral materials are of particular interest because they offer useful polarization properties without requiring bulk orientation of the molecules. This makes it possible to produce low cost optical elements such as circularly birefringent or circularly polarizing optical elements with potential applications in polarization manipulations and sensing. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 58–65, 2005     

Studies on the effects of gamma irradiation on nontoxic PVC formulations

Thirty-five PVC formulations were compounded initially from which selected nontoxic formulations were subjected to studies in changes of mechanical, optical, migratory, viscosity, and toxicity properties due to gamma irradiation to 2.5 M rads. Degree of discoloration was found to vary from negligible to intense discoloration after irradiation on the selected samples. The nontoxic character of all samples was retained after irradiation. One formulation (R₂) showed excellent radiation resistance and minimum discoloration. Effects of various additives on PVC radiation stability is also discussed.     

A highly transparent and thermally stable copolymer of 1‐adamantyl methacrylate and styrene

Thermal and optical properties of copolymers of 1‐adamantyl methacrylate (AdMA) and styrene (St) prepared by free radical polymerization in the bulk are investigated. The copolymer forms an azeotrope when the composition is AdMA/St = 55/45 mol%. The glass transition temperature and decomposition temperature of the azeotropic copolymer are 170 and ca 340 °C, respectively. The refractive index increases nonlinearly with St content from 1.522 to 1.591. The light scattering loss at 633 nm is 28.1 dB km^?1, which is less than half of that of polystyrene. The total optical loss including molecular vibrational absorption, which is evaluated using a copolymer‐based optical fiber, is 292–645 dB km^?1 at 500–700 nm. These values correspond to transmittances of 86–93% for a 1 m optical path length. © 2014 Society of Chemical Industry     

Synthesis of cationic UV‐curable methacrylate copolymers and properties of the cured films of their composites with alicyclic epoxy resin

Cationic UV‐curable methacrylate copolymers consisting of glycidyl methacrylate, iso‐butyl methacrylate, and 2,2,3,4,4,4‐hexafluorobutyl methacrylate were synthesized, and their structures were characterized by FTIR, ¹H NMR, and ¹³C NMR. A series of UV‐cured composite films based on the synthesized copolymers and an alicyclic epoxy resin, 3,4‐epoxycyclohexylmethyl‐3,4‐epoxycyclohexanecarboxylate (CE) were obtained through photopolymerization. Their surface contact angle, chemical ability, gloss, light transmittance, thermal behavior, micromorphology, and shrinkage were investigated. Results indicated that these cured resins showed excellent gloss and visible light transmittance; after the combination of the copolymers and CE, and in the presence of fluorine in the curing systems they exhibited relatively fine water resistance, chemical, and thermal stability. It was observed that these copolymers could decrease the degree of the volume shrinkage to CE. The UV‐curable materials may have promising applications in optical fiber coatings, flip chip and Organic Light‐Emitting Diode (OLED) packing. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and characterization of poly(dimethylamino ethyl methacrylate)–poly(ethylene oxide)–poly(dimethylamino ethyl methacrylate) triblock copolymers

Novel, monodispersed, and well‐defined ABA triblock copolymers [poly(dimethylamino ethyl methacrylate)–poly(ethylene oxide)–poly(dimethylamino ethyl methacrylate)] were synthesized by oxyanionic polymerization with potassium tert‐butanoxide as the initiator. Gel permeation chromatography and ¹H‐NMR analysis showed that the obtained products were the desired copolymers with molecular weights close to calculated values. Because the poly(dimethylamino ethyl methacrylate) block was pH‐ and temperature‐sensitive, the aqueous solution behavior of the polymers was investigated with ¹H‐NMR and dynamic light scattering techniques at different pH values and at different temperatures. The micelle morphology was determined with transmission electron microscopy. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Dielectric and Thermal Behavior of Ethyl and Butyl Methacrylate and N-p-cyano-phenyl Maleimide Copolymers

N-p-Cyano-phenyl maleimide PCPMI was prepared and copolymerized with ethyl and butyl methacrylate in order to study the effect of introducing a strong dipole along the polymer backbone. The copolymer composition was determined by elemental analysis and ¹H NMR spectroscopy. The molecular mass of the copolymers was determined by GPC. The glass transition temperature was measured and it was found to correlate well with the chemical structure, and increases with the increase of the maleimide content. The dielectric behavior of the homo methacrylate polymers and the copolymers was measured in the frequency range of 0.01 Hz to 10 MHz at different temperatures. The dielectric data were compared with the two Cole–Cole parameters equation. The glass transition temperature obtained from DSC measurements agreed well with the dielectric relaxation data.     

Design and synthesis of polymeric dispersant for water-borne paint by atom transfer radical polymerization

A series of chains of triblock amphiphilic copolymers were synthesized by atom transfer radical polymerization (ATRP) techniques and post modified to polymeric dispersant for waterborne paint. Poly(butyl acrylate (BA))-b-poly(hydroxy ethyl methacrylate (HEMA))-b-poly(methyl methacrylate (MMA)) triblock copolymers having predetermined molecular weights were synthesized by ATRP using CuBr, 2-bromoisobutyrate, and pentamethyldiethylenetriamine as a catalytic system in dioxane at 80 °C. The copolymers were further reacted with cyclic chlorophosphate and triethyl amine to form dispersible modified poly(BA-HEMA-MMA). The synthesized copolymers were structurally evaluated by Fourier transform infrared, ¹H NMR, ³¹P NMR, gel permeation chromatography (GPC), energy dispersive X-ray spectroscopy, and their hydroxyl equivalent, respectively. The surface activity of modified copolymers as dispersing additives was investigated by the surface tension analysis and wetting ability test. The ability of additives to function as wetting and dispersing agents was evaluated by analyzing their mechanical, optical, chemical, and rheological properties of water-based paints at different pigment volume concentrations. The effects of the chain length of copolymers on dispersibility and optical properties were studied. The optical properties of paints suggested that the dispersibility of modified poly (BA)-b-poly (HEMA)-b-poly (MMA) (MPBHM) increased with an increase in the molecular weight of the copolymer.     

Synthesis and nonlinear optical characterization of copolymers containing alternating 3,4‐dialkoxythiophene and (1,3,4‐oxadiazolyl)benzene units

We report the synthesis and linear and third‐order nonlinear optical (NLO) characterization of two novel copolymers containing alternating 3,4‐dialkoxythiophene and 1,4‐bis(1,3,4‐oxadiazolyl)benzene units. The copolymers were synthesized with a precursor polyhydrazide route. Both copolymers exhibited fluorescence around 430 nm under the irradiation of UV light. The NLO measurements were made with the single‐beam Z‐scan technique with Nd:YAG nanosecond laser pulses at 532 nm. The nonlinear refractive index of the investigated copolymers was negative, and the magnitude was as high as 10^?10 esu. The samples exhibited strong reverse saturation absorption and very good optical limiting properties at the wavelength used. The concentration dependence of third‐order NLO parameters was studied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Dielectric properties of lithium‐perchlorate‐filled acrylonitrile–hexyl methacrylate copolymer films

A series of poly(acrylonitrile‐co‐hexyl methacrylate), PAN‐co‐PHMA, copolymers with various hexyl methacrylate (HMA) contents were synthesized by emulsion technique. The incorporation of HMA units into the copolymers was confirmed by Fourier transform infrared and proton nuclear magnetic resonance (¹H‐NMR) spectroscopy. Glass transition temperatures (T _g) and thermal decomposition temperatures of copolymers were determined by differential scanning calorimetry and thermogravimetric analysis. The T _g of copolymers were lowered monotonically by increasing HMA content, while thermal stabilities of copolymers were enhanced. The frequency dependence of dielectric properties of three different amounts of LiClO₄ salt doped copolymer films was investigated. The influence of molar fraction of HMA on dielectric constant and ac‐conductivity of copolymer films was examined. Samples with higher HMA contents showed better stability and conductivity, as a result of increase in free volume and the mobility of the dipoles. The ac conductivity of copolymers was also improved by increasing LiClO₄ salt which was due to the existence of more charge carriers. PAN(88)‐co‐PHMA(12) copolymer with 1.5 mol% of lithium salt exhibited ionic conductivity of the 7.8 × 10⁻⁴ S/cm at 298 K. POLYM. COMPOS., 38:1792–1799, 2017. © 2015 Society of Plastics Engineers     

Synthesis and photopolymerization of acrylic acrylate copolymers

Acrylate‐functionalized copolymers were synthesized by the modification of poly(butyl acrylate‐co‐glycidyl methacrylate) (BA/GMA) and poly(butyl acrylate‐co‐methyl methacrylate‐co‐glycidyl methacrylate). ¹³C‐NMR analyses showed that no glycidyl methacrylate block longer than three monomer units was formed in the BA/GMA copolymer if the glycidyl methacrylate concentration was kept below 20 mol %. We chemically modified the copolymers by reacting the epoxy group with acrylic acid to yield polymers with various glass‐transition temperatures and functionalities. We studied the crosslinking reactions of these copolymers by differential scanning calorimetry to point out the effect of chain functionality on double‐bond reactivity. Films formed from acrylic acrylate copolymer precursors were finally cured under ultraviolet radiation. Network heterogeneities such as pendant chains and highly crosslinked microgel‐like regions greatly influenced the network structure and, therefore, its viscoelastic properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 753–763, 2002     

Synthesis and aqueous solution characterization of amphiphilic diblock copolymers containing carbazole

A series of near-monodisperse diblock copolymers of 2-(N-carbazolyl)ethyl methacrylate and 2-(dimethylamino)ethyl methacrylate (DMAEMA) of relatively low molecular weights (2600-24,000 g mol⁻¹) were synthesized by group transfer polymerization using tetrahydrofuran (THF) as a solvent. The molecular weight distributions and compositions of all the copolymers were obtained using gel permeation chromatography (GPC) in THF and proton nuclear magnetic resonance (¹H NMR) spectroscopy, respectively. Differential scanning calorimetry and thermal gravimetric analysis provided low glass transition temperatures (T_gs) of about 60 °C and decomposition temperatures between 320 and 450 °C for the copolymers, respectively. The three copolymers with the highest DMAEMA content were water-soluble below pH 7. Aqueous GPC at pH 3 showed that the water-soluble block copolymers formed micelles with apparent number average molecular weights above 100,000 g mol⁻¹.     

Synthesis of third-order nonlinear optical polyacrylates containing an azobenzene side chain via atom transfer radical polymerization

A series of polyacrylates containing different substituted-azobenzene chromophores were synthesized and polymerized via atom transfer radical polymerization. Nonlinear optical homopolymers containing an azobenzene side chain, of controllable molecular mass and low polydispersity (1.1–1.4) were obtained. In addition, side-chain copolymers were prepared in which the composition of the copolymers was controlled by using different feed ratios of the azobenzene monomer and methyl methacrylate. The third-order nonlinear optical properties of azobenzene monomers and their polymers were measured using the degenerated four-wave mixing technique. Each of the polymers displayed a high χ⁽³⁾ of about 10^?11 esu and rapid response time in femto-second magnitude. The effect of substituents on the azobenzene group and the composition of the polymer chain on the third-order nonlinear optical properties of the polymers were investigated.     

Synthesis and characterization of titanium dioxide optical films by sol–gel processes

The main purpose of this study is to synthesize the front panel of monitor with a high refractive index optical film. Our experiment uses titanium dioxide nanoparticles mixed with methyl methacrylate (MMA), 2‐hydroxyethyl methacrylate (2‐HEMA), and tri(ethylene glycol) dimethacrylate (TEGDMA) of the wet type and economical sol–gel production process. Our product has a superior mechanical, thermal, and optical properties was demonstrated by Fourier transform infrared spectrum (FTIR), differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), UV/visible spectrum, and Spectro Ellipsometer. In addition, we found the surface of the two series of thin film with the organic and inorganic high refractive index (TiO₂) mixed materials, has high transmittance for visible light above 90%, refractive index <1.65 and the hardness test 6H. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2271–2280, 2007     

New Vinyl Ester Bio-copolymers Derived from Dimer Fatty Acids: Preparation, Characterization and Properties

Two different vinyl ester resin monomers derived from dimer fatty acids (DA), dimer fatty acids polymerized glycidyl methacrylate (DA-p-GMA) resin and maleic anhydride modified dimer fatty acids polymerized glycidyl methacrylate (MA-m-DA-p-GMA) resin were prepared via simple ring-opening and esterification. FTIR, ¹H-NMR and GPC results demonstrated that these two target products have been successfully synthesized. Moreover, DA-based vinyl ester resin–styrene copolymers with different weight ratios were also prepared by a thermal polymerization, and their mechanical, morphological and thermal properties were investigated. Mechanical tests displayed that the prepared copolymers had excellent mechanical properties, and even at a low styrene content of 30 wt%, the copolymers still had excellent flexural strength of 29.14 MPa and tensile strength of 15.99 MPa. Micro-morphological investigation displayed that the copolymers had glossy and smooth impact resistance fractured surfaces, indicating distinctive fast brittle fracture features. Dynamic mechanical analysis (DMA) revealed that the copolymers’ glass-transition temperatures were within a broad range from 44 to 72 °C. Thermogravimetric results demonstrated that the copolymers had excellent thermal stability, as all copolymers showed a high thermal initial decomposition temperature above 390 °C.     

Design and synthesis of zero–zero-birefringence polymers in a quaternary copolymerization system

We designed and synthesized quaternary copolymers of methyl methacrylate (MMA), 2,2,2-trifluoroethyl methacrylate (TFEMA), benzyl methacrylate (BzMA), and 3,3,5-trimethylcyclohexyl methacrylate (TMCHMA) and we investigated their birefringence, thermal properties, and other optical properties. When the copolymer composition was MMA/TFEMA/BzMA/TMCHMA = 50:38:8:4, 40:30:7:23, or 30:21:7:42 (wt%), a zero–zero-birefringence polymer that exhibited neither orientational nor photoelastic birefringence was obtained. We demonstrated that such zero–zero-birefringence polymers with a variety of compositions could be successfully prepared in the quaternary system by using the same compensation method as applied in ternary random copolymerization. We also demonstrated that the glass-transition temperature (T_g) and refractive index (n_D) of these copolymers could be controlled with high accuracy while retaining their zero–zero-birefringence property. We can therefore predict the type of birefringence, the T_g, and the n_D of a particular copolymer before polymerization. Zero–zero-birefringence polymers with the most appropriate characteristics can then be synthesized selectively by quaternary copolymerization.     

High temperature stable photopatternable copolymers: Synthesis,optical properties,and photopatterning process studies

Photopatternable copolymers and photopatterning processes for high temperature stable optical elements have been studied. The photopatternable copolymers were synthesized from methyl methacrylate and methacrylic ester comprising a nonconjugate carbon–carbon double bond side chain and epoxy side chain. Their optical properties were investigated on film samples doped with m-benzoylbenzophenone (BBP). After irradiating with UV light, insoluble polymer was formed in a high yield at higher temperature, resulting in changes in thickness and refractive index, which were precisely controlled by the exposure energy of UV light. The two step photopatterning processes were carried out by means of UV irradiations with and without a photomask bearing a grating pattern followed by removal of unreacted BBP to draw an optical pattern on the polymer material with cross-linking. Further photoreaction was also performed to cure the polymer by exposure with a high energy UV lamp containing shorter wavelength light after the patterning process. By a combination of the patterning process and the postcuring process, an optical grating fabricated from these copolymers showed a heat stability up to 160°C. © 1994 John Wiley & Sons, Inc.