Physical Properties Of Copolymers Research Articles

Physical properties and DFT calculations of the hybrid organic polymeric nanocomposite thin film [P(An+o-Aph)+Glycine/TiO2/]HNC with 7.42% power conversion efficiency

Copolymer of aniline and ortho aminophenol was prepared by using the oxidative polymerization method with ferric chloride as an oxidizing agent in the occurrence of polyethylene glycol (Mol. Wt. 200) as a soft template. The microporous structure thin films were fabricated from the hybrid material of titanium oxide/copolymer (2-aminophenol and aniline) + glycine [P(An+o-Aph)+Gl/TiO2]HNC via a physical vapor deposition (PVD) method. The effect of the addition of glycine and TiO2 nanoparticles (NPs) on the physical properties of copolymer [P(An+o-Aph)] was discussed in light of the study of the crystallinity and optical properties. The addition of glycine increases the crystallinity of the resulting blend with the copolymer. The average crystallite size of TiO2 is ≈ 25 nm. The interaction between the blend and TiO2 was physical. The copolymer showed an absorbance of 1.18 at the wavelength (λ) 374 nm, which increased to 1.26 at λ= 440 nm after glycine addition, also increased to 1.53 at λ= 486 nm after TiO2 loading. Due to glycine blending and TiO2 addition, significant changes in the absorption index and indirect/direct bandgap of the copolymer have been detected. The materials Studio 7.0 program on TDDFT/DMol3 was used to optimize the molecular structure and perform the frequency calculations for the crystal models and isolated molecules. The DFT-Gaussian09W-vibration values are quite similar to the experimental data either in the structure or in the optical properties. The power conversion efficiency (η) of the blend Au/[P(An+o-Aph)+Gl]B/p-Si/Al heterojunction is 5.30 %, which increased to η=7.42% by loading the [TiO2]NPs to blend. The improvements in optical illuminations properties suggest the use the hybrid nanocomposite films in the polymers solar cell application.

Antimicrobial cationic acrylate-based hybrid coatings against microorganism contamination

Microorganism contamination on substrate surfaces is arousing increasingly concern as a serious health issue. In this study, we described fabricating antimicrobial cationic acrylate-based composite and investigating it as antimicrobial coatings of interior walls in buildings. Firstly, utilizing 3-(methacryloylamino) propyltrimethyl ammonium chloride (MPAC) and acrylates (BA, MMA) as monomers, a novel antimicrobial cationic acrylate-based copolymers (PAMs) was synthesized from surfactant-free emulsion polymerization (SfEP). The synthesis conditions, structures and physical properties of copolymers (PAMs) and its film (PAMs-F) were investigated through FT-IR, SEM, TEM and scratch test, etc. The results revealed that 6 % of MPAC and 0.5 % of KPS enabled the film-forming properties and enhanced conversion rate of PAMs, as well as endowed PAMs-F with significant antimicrobial activity. Furthermore, the PAMs based coating (PAMs-C) was prepared by PAMs and inorganic fillers. And the antimicrobial activity of PAMs-F and PAMs-C was measured, the effects of cationic monomer and nano-TiO2 were also investigated. The results indicated that PAMs-C was able to use to protect the building interior wall from microbial contamination.

Polymer Synthesis with More Than One Form of Living Polymerization Method.

Controlled radical polymerization (CRP) or controlled/living radical polymerization has revolutionized the polymer industry as a tool for the preparation of a wide variety of polymers. This process enables the preparation of polymers with good control of molecular weight, narrow polydispersity, and a range of architectures including block and graft copolymers, star polymers, and other functional polymers. The mechanistic transformation reaction provides a great opportunity to tune chemical and physical properties of copolymers. It can be applied to combine different homopolymers using post-modification techniques or by the use of a dual initiator, allowing the combination of mechanistically distinct polymerization reactions. This review will cover CRP transformations including the synthesis of block copolymers with both linear structures (AB, ABA, (AB) n , multiblocks, etc.) and branched macromolecular architectures (graft, miktoarm star, and dendritic-like), which are obtained by a combination of more than one form of living polymerization reaction.

A Comparative Study of Un-Modified and Modified Acrylate-SiO2 Nanocomposites

ABSTRACTBased on the nature of the links and interactions existing at the hybrid interface, hybrid materials can be broadly classified in two main designations: a) Hybrid compounds Class I, that include all systems with electrostatic forces, hydrogen bonding or Van der Waals interactions and b) Hybrid compounds Class II, showing that the inorganic and organic components are linked through strong covalent or ionic-covalent bonds. The physico–chemical properties of nanostructured copolymer acrylates based on butyl acrylate (BA), methyl methacrylate (MMA) and acrylic acid (AA) has been investigated employing un-modified SiO2 (Class I) and modified SiO2 particles (Class II) using 3-(trimethoxysilyl) propyl methacrylate (MPS) as compatibilizing agent. The synthesis was carried out using seeded batch emulsion polymerization system. Metastable nanostructured emulsions containing 1 wt% nanoparticles were obtained. Films casted from the in-situ nanostructured latex exhibited excellent optical transparency suggesting good nanoparticles dispersion. However, the mechanical properties showed by SiO2-MPS nanocomposite, are better than the Class I hybrid compounds. Therefore, SiO2-MPS surface treatment prior to polymerization enhances the physical properties of copolymer BA-MMA-AA film. The mass loss derivative traces for the polyacrylic nanocomposites and the neat polymer obtained by thermogravimetric analysis showed that the onset temperature for thermal decomposition was shifted towards a higher temperature than the neat polyacrylic, indicating the enhancement of thermal stability of the un-modified SiO2 nanocomposite. However, there is a decrease of 40°C in the decomposition temperature for the modified polyacrylic nanocomposite. The results obtained so far have shown that weak Van der Waals and H-bonding interactions may be sufficient to enable improvement of the physical properties of the acrylate nanocomposites.

Synthesis and characterization of crosslinked transparent poly(ester-urethane-acrylate) containing methyl methacrylate

The current study deals with the synthesis of various compositions of crosslinked poly(ester-urethane-acrylate) (PEUA)/methylmethacrylate (MMA) copolymer employing free radical polymerization. Initially, (1,4-butanediol) orthophthalate (BPE) polyester polyol has been synthesized by reacting 1,4 butanediol (BDO) and phthalic anhydride (PA). Subsequently the PEUA prepolymer was formed by reacting one mole of BPE with two mole of isophorone diisocyanate (IPDI) followed by end capping with two mole of 2-hydroxyethyl methacrylate (HEMA) in the presence of dibutyltin dilaurate (DBTL) catalyst. Finally, different compositions of crosslinked PEUA/MMA copolymer were prepared by reacting the PEUA prepolymer with MMA, in the presence of 1% azobisisobutyronitrile (AIBN) (w/w) as a chain initiator. The formation of BPE, PEUA and copolymers was confirmed by Fourier transform infrared (FT-IR) and 1H NMR spectroscopy. Water uptake, mechanical, thermal and optical properties of PEUA, PMMA and their copolymers have been also investigated. The impact fractured surface morphology of copolymers was observed using scanning electron microscope (SEM). The results showed that the increased miscibility, improved mechanical and physical properties of copolymer was influenced by the crosslink density. Dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), Haze and transparency of PEUA/MMAcopolymers were determined. The copolymer with 40 wt% MMA loading exhibited optimum mechanical and physical properties with respect to the other compositions.

Controlling Macroscopic Properties by Tailoring Nanoscopic Interfaces in Tapered Copolymers

Systematic variation of comonomer concentration in individual polymer chains is responsible for unique phase behaviors in different types of copolymers. Controlled self-assembly of gradient copolymers into desired morphologies is theoretically understood but practically challenging, and identifying heterogeneous phase partitioning of individual comonomers in those resulting morphological regions can be difficult. Building on previous work where improved methods were used to elucidate heterogeneous comonomer partitioning in styrene–butadiene gradient copolymers [Clough Macromolecules 2014, 47, 2625], the arrangement of the styrene and butadiene monomers in only a fraction of the total chain length is used here to significantly perturb the overall morphology and physical properties of copolymers. Importantly, the chemical composition of all copolymers was held nearly fixed in this study. The resulting tapered and inverse tapered block copolymers contain nanometer length scale interfaces that differ from one another and differ dramatically from that observed in a control block copolymer composed of chains with a discrete interface. Evidence is presented that butadiene can reside in rigid environments, styrene can reside in mobile environments, and their relative amounts can be varied based on the gradient design. The connection between the molecular design of the gradient, the resulting nanometer-length scale interfacial structures, and mechanical properties is demonstrated using a combination of variable temperature solid-state NMR, modulated DSC (differential scanning calorimetry), AFM (atomic force microscopy), and rheology experiments.

Synthesis and characterization of electrically conducting copolymers of poly(aniline-co-o-iodoaniline)

Functionalized copolymers of poly(aniline-co-o-iodoaniline) have been synthesized by the chemical oxidative polymerization method by using o-iodoaniline (o-IA) and aniline (AN) as monomer units by changing their molar feed ratio in acid aqueous medium. The physical properties viz; solubility, electrical conductivity have been studied to characterize them. The copolymers possess better solubility than unsubstituted homopolymer in organic solvent such as N -methyl-2-pyrrodinone (NMP). The conductivity of the pressed pellets of as-synthesized copolymers depends upon the content of o-IA in the polyaniline (PANI). The structural confirmation of the copolymer has been explained by Fourier transform infrared spectroscopy study which suggest that AN and o-IA units are uniformly distributed along the polymer chain and thus, the physical properties of copolymers may possibly be tailored by varying the molar feed ratio in copolymerization reactions. The conductivity of the copolymer decreases upon increasing the o-IA content in molar feed, because the introduction of –I- as a functional group reduces the extent of conjugation of the polymer chain.

Effects of Ag/Pt Nanoparticles on the Physical Properties of Copolymers Containing 2-Fluoro-5-Methylanisole

The ophthalmic materials must satisfy the optical requirements, physical and chemical stability and fulfill biological requirements, such as biocompatibility to be used in hydrogel ophthalmic lenses. Polymeric materials for hydrogel lenses were prepared by the copolymerization of HEMA, NVP, MMA, EGDMA and FMA in the presence of antibacterial Ag and Pt nanoparticles and also the effect of these copolymers containing nanoparticles on oxygen transmissibility was then investigated. The combination where AgNPs were added produced a light-yellowish colored transparent ophthalmic lens. The copolymers containing Ag and Pt nanoparticles did not have significant impact on the water content and refractive index of the hydrogel contact lens, but the Ag/Pt nanoparticles reduced oxygen permeability to a certain extent. Furthermore, the spectral transmittance significantly decreased. The additive, 2-fluoro-5-methylanisole, did not effect significantly on the physical properties of the polymer, but it was able to block UV light to a certain extent. The water content and oxygen permeability slightly increased as the amount of FMAs increased.

New insights into poly(lactic-co-glycolic acid) microstructure: using repeating sequence copolymers to decipher complex NMR and thermal behavior.

Sequence, which Nature uses to spectacular advantage, has not been fully exploited in synthetic copolymers. To investigate the effect of sequence and stereosequence on the physical properties of copolymers, a family of complex isotactic, syndiotactic, and atactic repeating sequence poly(lactic-co-glycolic acid) copolymers (RSC PLGAs) were prepared and their NMR and thermal behavior was studied. The unique suitability of polymers prepared from the bioassimilable lactic and glycolic acid monomers for biomedical applications makes them ideal candidates for this type of sequence engineering. Polymers with repeating units of LG, GLG and LLG (L = lactic, G = glycolic) with controlled and varied tacticities were synthesized by assembly of sequence-specific, stereopure dimeric, trimeric, and hexameric segmer units. Specifically labeled deuterated lactic and glycolic acid segmers were likewise prepared and polymerized. Molecular weights for the copolymers were in the range M(n) = 12-40 kDa by size exclusion chromatography in THF. Although the effects of sequence-influenced solution conformation were visible in all resonances of the (1)H and (13)C NMR spectra, the diastereotopic methylene resonances in the (1)H NMR (CDCl(3)) for the glycolic units of the copolymers proved most sensitive. An octad level of resolution, which corresponds to an astounding 31-atom distance between the most separated stereocenters, was observed in some mixed sequence polymers. Importantly, the level of sensitivity of a particular NMR resonance to small differences in sequence was found to depend on the sequence itself. Thermal properties were also correlated with sequence.

Synthesis and characterization of amphiphilic pluronic (F68)‐1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphoethanolamine copolymers and their micelles as a drug carrier

AbstractA new Pluronic (F68)‐1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphoethanolamine (DPPE) (Pluronic (F68)–DPPE) copolymer was synthesized with Pluronic (F68) and DPPE. The chemical structure and physical properties of copolymers were determined by FTIR, 1H NMR, 13C NMR, 31P NMR, and TGA. Environmental scanning electron microscopy, fluorescence spectroscopy, and dynamic light scattering method confirmed the formation of copolymeric micelles of Pluronic (F68)‐DPPE. To estimate the feasibility as novel drug carriers, the copolymer micelles were prepared by the phase separation dialysis method. Amphotericin B as a lipophilic model drug was incorporated into copolymeric micelles and the drug release behavior was investigated. It was found that the chemical composition of the micelle was a key factor in controlling micelles size, drug‐loading content, and drug release behavior. As DPPE segment weight ratio increased, the micelle size and drug‐loading content increased, and the drug release rate decreased. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Synthesis and physico-chemical properties of copoly(ester-sulfonates) of 1,1 ′-bis (3-methyl-4-hydroxy phenyl) cyclohexane with 2,4-toluene disulfonyl and terephthaloyl chlorides

Copoly(ester-sulfonates) of varying compositions have been synthesized by interfacial polycondensation technique by using H 2O–CHCl 3 as an interphase, alkali as an acid acceptor and sodium lauryl sulfate-cetyl trimethyl ammonium bromide as mixed emulsifiers at 0 °C for 4 1 2 h. Copolymers are characterized by IR and NMR spectral data, viscosity in three different solvents at three temperatures and little solvent and temperature effect is found on [ η]; and density (1.3430–1.3406 g/cm 3) by floatation method. Copolymers possess excellent solubility in common solvents and chemical resistance against water, acids, alkalis and salts. They possess moderate to good tensile strength (10.6–79.5 N/mm 2), excellent volume resistivity (7.5–28 × 10 16 Ω cm), electric strength (53–118 kV/mm) and dielectric constant (1.3–1.58). They are thermally stable up to about 349–373 °C in an N 2 atmosphere and possess high T g (136–196 °C). DTA endo/exothermic transitions supported either decomposition or formation of new product(s). Physical properties of copolymers are improved with increasing terephthlate content.

Cationic copolymerization of tetrahydrofuran with ethylene oxide in the presence of diols: Composition, microstructure, and properties of copolymers

Cationic copolymerization of tetrahydrofuran (THF) with ethylene oxide (EO) in the presence of diols leads to dihydroxy terminated telechelic copolymers. In the present article the influence of copolymerization conditions on the copolymer structure was studied in view of conclusions derived from studies of copolymerization kinetics and mechanism. It was shown that according to established copolymerization mechanism, the number average molecular weights increase linearly with conversion up to Mn ≅ 2500, hydroxyl end groups are bound exclusively to EO units and copolymers are composed of [EO]–[THF]y segments. Microstructure of copolymers may be to some extent regulated by changing reaction conditions. Some physical properties of copolymers also were studied. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3455–3463, 1999

Physical properties of 2-acetoxyethyl methacrylate and 2-hydroxyethyl methacrylate copolymers

2-Acetoxyethyl methacrylate (AcEMA) has been synthesized from 2-hydroxyethyl methacrylate (HEMA) and polymers and copolymers of the two monomers have been prepared. The effect of composition on the physical properties of the copolymers has been evaluated by d.s.c. and determination of tensile mechanical properties, both on dry and wet samples, flexural dynamic mechanical properties (d.m.t.a.) on dry samples, and water sorption and desorption kinetics. The addition of the more flexible component (AcEMA) significantly lowers the copolymer glass transition and affects its overall properties. These differences are explained by the d.m.t.a. measurements, with storage and loss moduli strongly depending on the copolymer composition. The mechanical behaviour of the copolymers ranges from glassy to rubbery, as a function of composition, with elastic moduli in the range of 100–2500 MPa for dry copolymers and 35-0.3 MPa for wet copolymers. Similarly, the equilibrium water content is affected by the balance of hydrophobic-hydrophilic monomer content, with a higher amount of water being absorbed in copolymers containing less AcEMA.

Graft copolymerization of wool using some acrylate monomers. III. Physical properties of copolymers

AbstractSome physical properties of the graft copolymers of wool with acrylate monomers namely, methylacrylate, ethylacrylate, n‐butylacrylate and methylmethacrylate are investigated. The results show that the moisture regain decreases considerably after grafting; the density also decreases after an initial increase at low percentage of polymer deposition. With the grafting of low Tg polymers the breaking elongation increases, initial modulus decreases and elastic recovery increases; a reverse trend is found with the grafting of high Tg polymers. The dynamic mechanical properties of all grafted samples are also reported.

Sequence Distribution in Copolymers Physical Property Studies

Abstract The physical properties of copolymers are determined by their compositions and by the distribution of monomeric sequences in their chains. In some cases, sequence distributions can be determined from or correlated with physical properties observed for copolymers. Such determinations or correlations are relatively simple when calculations are based on run numbers.

Sequence Distribution in Copolymers

AbstractThe physical properties of copolymers are determined by their compostions and by the distribution of monomeric sequences in their chains. In some cases, sequence distributions can be determined from or correlated with physical properties observed for copolymers. Such determinations or correlations are relatively simple when calculations are based on run numbers.