Chemical Structure Of Poly Research Articles

Synthesis and characterization of amino-functional polyesters composed of lactic acids and serine amino acids

Functional polyesters with good biocompatibility are always important biomaterials. In this study, poly (latide-co-N-trityl serine ester)s (P (LA-co-TSL)s) were synthesized through the copolymerization of lactide (LA) and N-trityl serine lactone (TSL) in toluene under 90 °C with the catalysis of diethylzinc. The molecular weight (Mn) of P (LA-co-TSL) with different TSL molar ratios (4.5%, 8.8%, 25.2%, 41.7% and 100 mol%) ranged from 3.7 kDa to 7.2 kDa with the polydipersity index (PDI) from 1.40 to 1.57. The chemical structure of poly (LA-co-TSL)s was characterized by FTIR, 1H NMR and 13C NMR spectroscopy. As the proportion of TSL in P (LA-co-TSL) increased, the glass transition temperature (Tg) of P (LA-co-TSL) increased gradually, from 56 °C of PLA to 161 °C of Poly (TSL). The initial weitht loss temperature of P (LA-co-TSL) increased as the ratio of TSL increased, from 172 °C of PLA to 230 °C of Poly (TSL). Upon removal of the N-trityl protecting group, amino functional poly (latide-co-serine ester) (P (LA-co-SL)) was realized and confirmd by FTIR and 1H NMR spectra. GPC displayed approximately 19.5% polyester backbone degradation during deprotection with trifluoroacetic acid. DSC analysis illustrated better crystallization properties of the copolyester after amino group deprotection. Using mPEG as an initiator, a new type of block copolymer, mPEG-b-poly (latide-co-N-trityl serine ester)s (mPEG-b-P (LA-co-TSL)s), was obtained. After N-trityl removal, mPEG-b-P (LA-co-TSL) displayed excellent cytocompatibility in L929 cell culture experiments.

Chemically bound hydrophobic modification in hydrogel surface layer using poly(N-vinylamide)s

The novel hydrophobic surface modification of hydrogel structure, referred to as organohydrogel, was firstly achieved through the utilization of poly(N-vinylamide)s hydrogels, taking advantage of the property of polycation precursor. Following the shrinkage of poly(N-acetamide-co-N-vinylformamide), only the surface moiety was subjected to hydrolysis. Subsequently, a radical initiator was chemically tethered to the amino groups on the hydrogel surface to facilitate atom transfer radical polymerization (ATRP) of hydrophobic monomer, phenylethylacrylate. Hydrophobic layer characteristics were differentiated by varying hydrolysis time (xt) and ATRP time (yt), resulting in the creation of hydrophobic surface-modified gel (HSMgel). All HSMgels resulted in stable swelling ratio (S.R.) regardless of yt. The contact angle of water droplets increased gradually with both increasing xt and yt, from 17.6° to 91.9°, while maintaining a relatively constant S.R. The drying process of hydrophobic surface-modified HSMgels was accelerated, while that of precursor hydrophilic gels was delayed. These unique properties stemmed from the chemical structure of poly(N-vinylamide)s, which led to the formation of a chemically bound hydrophobic layer within the hydrogels.

EPOXY RESIN, VINYL COPOLYMER, AND RICE HUSK SILICA BASED TERNARY NANOCOMPOSITES: FABRICATION, MECHANICAL CHARACTERISTICS, AND THERMAL AGING

In this research, the bio-composites based on epoxy resin filled with nano-silica and vinyl copolymer were fabricated using diethylene triamine as a curing agent and casting method. The vinyl copolymer was synthesized from Hydroxyethyl Acrylate and Methacrylic acid using ammonium persulfate as an initiator. The bio-silica was extracted from rice husk via a simple technique of acid treatment and calcination. The chemical structure of poly(HEA-Co-MAA), silica was confirmed with help of the FTIR, and NMR-1H. The high-speed mechanical stirrer was used to obtain the good dispersion of silica and poly(HEA-Co-MAA) in epoxy resin before mixing and curing with Diethylenetriamine (DETA) hardener. The thermal stability of cured epoxy resin was enhanced with the presence of rice husk silica and poly(HEA-Co-MAA). The composite sample with 1 wt.% of bio-silica and 3 wt.% of poly(HEA-Co-MAA) showed the best mechanical properties with an improvement of up to 28.82%; and 35.36% of impact strength and tensile strength, respectively when compared with a pristine sample. The aging testing was also performed to investigate the effect of additive added on the thermal resistance of epoxy resin.

A polyacetylene based polyelectrolyte via non-catalyst polymerization of 2-ethynylpyridine and 3,4-dimethoxy benzoyl chloride

A new polyacetylene based polyelectrolyte, poly(N-3,4-dimethoxybenzoyl-2-ethynylpyridinium chloride), was synthesized by the direct polymerization of 2-ethynylpyridine and 3,4-dimethoxybenzoyl chloride. The polymerization successfully proceeded without any additional catalyst or initiator to give a high yield of the product. The chemical structure of poly(N-3,4-dimethoxybenzoyl-2-ethynylpyridinium chloride) was confirmed using 1H and 13C nuclear magnetic resonance spectroscopy, as well as Fourier transform infrared spectroscopy. Further, optical properties, electrochemical properties, and thermal stabilities were investigated by cyclic voltammetry, UV-Vis absorption spectra, photoluminescence spectra, thermogravimetric analysis. Comparing UV-Visible absorption and photoluminescence spectrum, the polymer showed the band gap of 2.18 eV and photon energy of 2.58 eV.

Synthesis, characterisation and pre-evaluation of a novel terpolymer as pour point depressants to improve the Malaysian crude oil flowability

Wax deposition is considered one of the most serious operational issues in the crude oil pipelines. This issue occurs when the crude oil temperature decreases below the temperature of wax appearance and paraffin wax starts to precipitate on the pipelines’ inner walls. As a result, the crude oil flow is impeded because of the precipitated wax. The use of polymeric pour point depressants has obtained significant interest among researchers as an approach of wax control for enhancing the flowability of the waxy crude oil. PPD of poly(behenyl acrylate -co-stearyl methacrylate-co- maleic anhydride) (BA-co-SMA-co-MA) was facilely synthesised by the use of free radical polymerisation. The variation of the PPD structure was studied by choosing several essential parameters like monomers ratio, reaction time, initiator concentration, and reaction temperature. Furthermore, viscosity measurement, pour point, and cold finger apparatus have been employed to evaluate the efficiency of the synthesised Polymer. The chemical structure of poly(BA-co-SMA-co-MA) has been identified through the use of Fourier transform infrared as well as nuclear magnetic resonance. The experimental findings demonstrated that the ideal conditions for obtaining the highest yield were 1.5% initiator concentration, reaction time and temperature of 8 h and 100 °C, respectively, and monomer ratio of 1:1:1 (BA:SMA:MA). Under these ideal conditions, the prepared terpolymer reduced the crude oil viscosity at 30 °C and 1500 ppm from 7.2 to 3.2 mPa.s. The cold finger experiment demonstrated that after poly(BA-co-SMA-co-MA) was used as a wax inhibitor, the maximum efficiency of paraffin inhibition of 45.6% was achieved at 200 rpm and 5 °C. Besides, the best performance in depressing the pour point by ΔPP 14 ℃ observed at the concentration of 1500 ppm, which can change the growth characteristics of wax crystals and delay the aggregation of asphaltene and resin, thus effectively improving the flowability of crude oil.

Influence of the Degradation Medium on Water Uptake, Morphology, and Chemical Structure of Poly(Lactic Acid)-Sisal Bio-Composites.

A series of poly(lactic acid) (PLA) and poly(lactic acid)-based bio-composites (sisal PLA) were prepared and studied by spectroscopic and microscopic techniques as such and after immersion at room temperature in different degradation mediums (i.e., distilled and natural sea water and solutions at pH = 2, 6, and 8). In these conditions, some of their macroscopic and microscopic properties were monitored during a period of 30 days. Water absorption increased with the increasing fiber content regardless of the immersion medium. The maximum water absorption was achieved at pH = 8 (~16%), indicating a more severe action of the alkaline mediums on the samples. The diffusivity, D, of PLA decreased with the addition of fibers and acidic mediums showed higher D, indicating higher diffusivity of water through the specimens with respect to those submerged in moderate or alkaline mediums. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis evidenced a weak interaction between the PLA matrix and the sisal fibers. Very limited degradation phenomena occur in our conditions: Despite some changes in the microstructure, the PLA backbone seems to be largely resistant to hydrolysis, almost regardless of the pH value and even at the highest sisal content.

Structure and Properties of Biodegradable Poly (Xylitol Sebacate-Co-Butylene Sebacate) Copolyester.

In this work, a bio-based copolyester with good mechanical properties was synthesized and characterized in terms of structure, main properties and biodegradability Determining the chemical structure of such materials is important to understand their behavior and properties. Performing an extraction of insoluble cross-linked polymer using different solvents allowed us to analyze how the polymer behaves when subjected to different chemical environments, and to obtain soluble samples suitable for more in-depth analysis. Chemical structure of poly (xylitol sebacate-co-butylene sebacate) was determined by a 1H NMR and FTIR analysis of both prepolymer gel sample and samples obtained by extraction of cross-linked polymer using different solvents. Block structure of the copolymer was confirmed by both NMR and DSC. Gel fraction, swelling value, water contact angle, and mechanical properties were also analyzed. Biodegradability of this material was confirmed by performing enzymatic and hydrolytic degradation. Synthesizing sugar-alcohol based copolyester using three monomers leads to obtaining a material with interesting chemical structure and desirable mechanical properties comparable to conventional elastomers.

Fabrication of Hydrogen-Selective Silica Membranes via Pyrolysis of Vapor Deposited Polymer Films

Efficient separation of hydrogen under steam reforming conditions is important for the development of clean energy sources. Although high-temperature and steam-stable membranes with high fluxes and large separation factors would be valuable for such an application, their fabrication remains a challenge. Silicon-based ceramic membranes are particularly promising due to their high temperature resistance and excellent chemical stability. In this study, we propose a new synthetic route for fabricating nanoporous, asymmetric membranes via the pyrolysis of silicon-containing polymer films deposited by initiated chemical vapor deposition (iCVD) on macroporous silicon carbide supports. Specifically, we systematically investigated the change in the chemical structure of poly(2,4,6,8-tetravinyl-2,4,6,8-tetramethyl cyclotetrasiloxane) films at different pyrolysis temperatures and found that the complete transition to a silica membrane occurred at ∼1100 °C. Three different supports composed of silicon carbide powders...

Synthesis and Characterization of Poly[N-(3-butynyl)-2-ethynylpyridinium bromide

A new conjugated polyelectrolyte with the N-(3-butynyl)pyridinium bromide was synthesized via the non-catalyst polymerization of 2-ethynylpyridine by using 4-bromo-1-butyne. The polymerization proceeded well to give the resulting poly[N-(3-butynyl)-2-ethynylpyridium bromide] in 75% yield. The chemical structure of poly[N-(3-butynyl)-2-ethynylpyridium bromide] was characterized by such instrumental methods as IR, NMR, and UV-visible spectroscopies to have the conjugated backbone system with the designed substituents. The electro-optical and electrochemical properties of polymer were measured and discussed. Comparing absorption spectrum and cyclic voltammetry data, this polymer had the HOMO and LUMO values of 5.33 and 3.35 eV, which means the band gap of 1.98 eV.

Chemical structure, water absorbency and thermal properties of poly(acrylamide-co-acrylic acid)-grafed-poly(styrene-co-methyl methacrylate) “raspberry” – shape like structure microgels

This contribution presents the characterization of poly(acrylamide-co-acrylic acid)-grafted-poly(styrene-co-methyl methacrylate) [poly(AAm-co-AAc)-g-poly(St-co-MMA)] The chemical structure of poly(AAm-co-AAc)-g-poly(St-co-MMA) microgels was proposed. The effect of MBA contents on the degree of cross-linking (%), water absorbency (EWC, %), glass transition temperature, Tg and thermal degradation were studied. The degree of cross-linking (%) and EWC, % increased at 1.5 to 1.675 wt.% of MBA might be due to mono cross-links of MBA. The fluctuation of Tg and melting temperature (Tm) from 1.85 to 2.2 wt.% of MBA might be due to di, poly and cyclic cross-links of MBA. Decomposition of poly(AAm-co-AAc)-g-poly(St-co-MMA) was slightly affected by increasing in MBA contents from 1.5 to 2.2 wt.%. Tg of poly(AAm-co-AAc)-g-poly(St-co-MMA) was decreased at 1.5 to 1.675 wt.% of MBA due to increase in ordered structure and crystallinity content, which led to an increase in Tm.

Synthesis and characterization of a polyacetylene derivative: Poly(N-methylpropargylamine)

ABSTRACTThe polymerization of N-methylpropargylamine was carried out by var-ious transition metal catalysts. The polymerizations of N-methylpropar-gylamine using the Pd, Pt, and Ru chlorides proceeded well in mild homogeneous manner to give the corresponding polymers in moderate yields. The chemical structure of poly(N-methylpropargylamine) was characterized by such instrumental methods as NMR (1H-, 13C-), IR, UV-visible spectroscopies, and elemental analysis to have the designed conjugated polymer structure. The photoluminescence peak of poly(N-methylpropargylamine) was observed at 444 nm, which is corresponded to the photon energy of 2.79 eV. The electrochemical properties were also measured and discussed.

Electro-optical and electrochemical properties of poly(1-ethynyl-4-phenoxybenzene)

ABSTRACTA polyacetylene derivative with 4-phenoxyphenyl substituent was synthesized by the polymerization of 1-ethynyl-4-phenoxybenzene. The chemical structure of poly(1-ethynyl-4-phenoxybenzene) was characterized by NMR (1H-, 13C-), IR, and UV-visible spectroscopies to have a conjugated polymer backbone with the 4-phenoxyphenyl substituents. The polymer showed characteristic UV-visible absorption maximum value of 352 nm. Photoluminescence spectrum exhibited maximum peak at 453 nm, which corresponds to the photon energy of 2.74 eV. Band gap of polymer was 3.02 eV.

Improved understanding on the reinforcement of low-temperature hydrogenated nitrile butadiene rubber composites by in situ polymerization of unsaturated metal methacrylate: influences of salt cation

The morphology and chemical structure of poly(UMM) and the solubility of UMM induced by its cations have a remarkable impact on reinforcement of rubber matrices.

Poly(melamine-co-formaldehyde) methylated effect on the interface states of metal/polymer/p-Si Schottky barrier diode

The deposition technique and interface effect of polymeric molecules onto silicon surface is crucial topic for organic/inorganic hybrid technologies. In this study, the chemical structure of poly(4-vinyl phenol) (PVP) has been modified by cross-linked agent in solution for deposition onto p-Si surface. The poly(melamine-co-formaldehyde) methylated (PMF) has been used as a cross-linked agent for PVP polymeric molecules to apply spin cast deposition technique. The rectification ratio and interface states have been improved with PMF cross-link agent compared with only PVP polymeric layer. Some important diode parameters such as diode ideality factor (η), barrier height (ϕb), interface state density (Nss), series resistance (Rs) of the Au/PVP:PMF/p-Si structure were calculated from the current–voltage (I–V) characteristics. The ideality factor and barrier height were found to be 2.37 and 0.71. For the explanation of the deviation of ideality factor value from 1, the interface states has been investigated by the frequency dependent capacitance (C–f–V) and conductance (G–f–V) techniques at room temperature. It is found that the interface states and Rs which indicate the deviation of the ideality factor of Au/PVP:PMF/p-Si structure is strongly depended on bias voltage and frequency.

Ring-opening polymerization of l-lactide and ε-caprolactone catalyzed by versatile tri-zinc complex: Synthesis of biodegradable polyester with gradient sequence structure

An economic and biocompatible Schiff base tri-zinc catalyst was used to synthesize homo/copolymers of l-lactide (LA) and ε-caprolactone (CL) in bulk at first time. Both 1H and 13C NMR analyses show that LA is more active than CL, resulting in a poly(LA-grad-CL) copolymer with gradient sequence structure. A series of copolymers containing varying LA/CL ratios were readily synthesized. The chemical structure of poly(LA-grad-CL) was fully investigated using NMR and GPC technologies. TGA, DSC, DMA and nanoindentation instruments were employed to evaluate thermal and mechanical properties of these polymers. The results indicate that polymer composition and chain structure have a great impact on the crystallization behavior and crystallinity, as well as the thermal and mechanical properties of the copolymers. Therefore, the performance of the copolymer can be then tailored by simply adjusting the ratios of LA to CL.

Thermal Behavior and Photovoltaic Performance of Fullerene Grafted Dehydrochlorinated Poly(Vinyl Chloride) in Bulk Heterojunction Solar Cells

This study describes the development of an alternative conducting polymer for organic photovoltaic cell application. Chemical structure of poly(vinyl chloride) (PVC) was modified by two reactions, dehydrochlorination followed by fullerenation. The aim of this work was to explore the feasibility of using this chemically modified PVC (C60-g-DHPVC) as an electron acceptor phase in ITO/PEDOT:PSS/P3HT:acceptor/TiOx/Al bulk heterojunction (BHJ) solar cell. From the result, it was found that the power conversion efficiency of the BHJ cell employing PCBM as an electron acceptor alone increased from 0.5% to the maximum value of 1.34%, after the addition of C60-g-DHPVC.

Synthesis and properties of poly(arylene ether ketones)

The results of investigations of the synthesis and properties of poly(arylene ether ketones) prepared by electrophilic and nucleophilic substitution reactions are generalized and described systematically. Data on the effect of the polycondensation conditions on the molecular weight and properties of polymers are considered. A scientific knowledge about the effect of the synthesis conditions and the chemical structure of poly(arylene ether ketones) on their properties enabled the directed synthesis of polymers. Such polymers possess a complex of valuable performance (high thermal stability, good heat, chemical and mechanical resistance combined with unique specific impact strength), engineering, and new electrophysical properties.

A Metal-Ion Adsorbent Based on Composite of Graphene Oxide/Poly (1-(3-aminopropyl) Pyrrole)

A novel metal-ion adsorbent was developed based on graphene oxide (GO) and poly (1-(3-aminopropyl) pyrrole. Firstly, GO was covalently functionalized by 1-(3-aminopropyl) pyrrole (APP) monomer by an esterification reaction between the carboxyl groups of GO and the amine groups of APP. Subsequently, a GO/poly (1-(3-aminopropyl) pyrrole) (poly (GO-APP)) composite was prepared by in situ crosslinking polymerization.The chemical structure of poly (GO-APP) composite was determined by a series of characterization methods, such as Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM) and Thermogravimetric analysis (TGA).The poly (GO-APP) was a hard solid material like a coal (Figure a), which is due to the crosslinked polymerization between GO and polymer. In this composite system, the GO is a crosslinking agent like a polyfunctional monomer, which can turn the linear polymer into crosslinked network polymer to increase the stiffness, strength and stability of poly (GO-APP).This poly (GO-APP) composite is used for the adsorption of metal ions. As shown in Figure b, the absorption capacity of poly (GO-APP) was much larger than that of GO. The sorption of metal ions is based on both nitrogen and oxygen functional groups. The oxygen-containing functional groups in GO and the protonated amine groups in APP can bind to cations easily. Moreover, the chemical affinity of metal ions for amine groups is stronger than that for oxygen-containing functional groups. Therefore, the absorption capacity increases with the content of APP monomer.Besides, the poly (GO-APP) showed a conducting property due to the conjugated π-π system in the main chain of copolymer, which will greatly expand the application fields of poly (GO-APP) composite.

Synthesis and Characterization of a Polyacetylene Derivative with Hydroxy Functional Groups

A fluorenyl group-containing polyacetylene, poly(9-ethynyl-9-fluorenol) was prepared by the polymerization of 9-ethynyl-9-fluorenol (EF) by [(nbd)RhCl]2. The polymerization proceeded well in homogeneous manner to give in high yield of polymer. The chemical structure of poly(EF) was characterized by such various instrumental methods as NMR, IR, and UV-visible spectroscopies to have the poly(EF) have a conjugated polymer backbone system with the designed fluorene groups. Poly(EF) showed edge range of UV-visible absorption spectrum about 600 nm and the band gap of poly(EF) was 2.20 eV. The maximum photoluminescence peak was observed at 431 nm.

Fast fabrication of superabsorbent polyampholytic nanocomposite hydrogels via plasma-ignited frontal polymerization

We report the facile synthesis of poly(VI-co-MAA) superabsorbent polyampholytic hydrogels (VI = N-vinylimidazole, MAA = methacrylic acid) via plasma-ignited frontal polymerization (PIFP). On igniting the top surface of the reactants with air plasma, frontal polymerization occurred and poly(VI-co-MAA) hydrogels were obtained within minutes. The preparation parameters were investigated, along with swelling capacity, morphology, and chemical structures of poly(VI-co-MAA) hydrogels. Interestingly, the hydrogels are superabsorbent in water and show ampholytic characteristic toward pH. Moreover, the hydrogels are able to capture cationic dyes through electrostatic interaction, offering the potential for further development as dye adsorbents for water purification. In addition, nanocomposite hydrogels were obtained by embedding quantum dots (carbon dots or CdS nanocrystals) into the polymer matrix, which endows the nanocomposite hydrogels with favorable fluorescence and potential applications in bioimaging and biosensing. The results indicate that FP can be applied as an alternative means for facile synthesis of multifunctional hydrogels with additional efficiency and energy-saving. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 912–920