Application of Hydrosoluble Polymers to Preparation of Nanoscale Calcium Hydroxide

Calcium hydroxide with uniform diameters about 50—100 nm was firstly prepared under moderate condition by adding different kinds of hydrosoluble polymers. From the results of TEM and IR, the polymers were proved not only to improve the agglomeration of the nanoparticles but also to be used as a template to control the formation of the special structure and the needed size of Ca(OH) 2 by changing the concentration of the polymers. The experimental results of TG-DTA indicate that the Ca(OH) 2 can absorb most of the acid gases released during the decomposition of polymers. So this kind of nano- Ca(OH) 2 can be used as a useful additive of environmental friendly plastics.

Research Progress on the Preparation of Inorganic/Natural Materials Composite Microspheres

Microspheres are a new type of drug carrier with great potential for development and application.Natural polymers have good biocompatibility,biodegradability,and are easily dispersed in living organisms,making them suitable for preparing microspheres.Inorganic materials(mainly inorganic minerals)have excellent mechanical properties and are inexpensive and easy to obtain.Through the coupling and hybridization of natural polymers and inorganic materials,they can complement each other's advantages and synergistically enhance efficiency,resulting in many excellent physical and chemical properties.Inorganic materials/natural polymer composite microspheres can be prepared by modifying natural polymers with inorganic materials through various methods such as emulsification crosslinking,solution mixing,in-situ synthesis,extrusion,etc.The application of inorganic materials/natural polymer composite microspheres in drug delivery systems has significant sustained-release effects,is safe and non-toxic,and the cost of carrier materials is relatively low,which has certain significance for the development of new drug carriers.This article reviews the recent research on the preparation,drug loading and release properties of inorganic material/natural polymer composite microspheres,analyzes the advantages and disadvantages of commonly used preparation methods,and looks forward to the development direction of composite microspheres.

A review of recent progress in preparation of hollow polymer microspheres

The preparation methods of hollow polymer microspheres both at home and abroad are summarized, and their preparation mechanisms and developmental states are presented. These methods include the liquid droplet method, dried-gel droplet method, self-assembly method, microencapsulation method, emulsion polymerization method and the template method. Hollow polystyrene microspheres are the most extensively studied in the research of hollow polymer microspheres. Through comparison of the advantages and disadvantages of different preparation methods, it is concluded that microencapsulation method is most suitable for preparing polystyrene hollow microspheres.

Advancements in the preparation of high-performance liquid chromatographic organic polymer monoliths for the separation of small-molecule drugs

The various advantages of organic polymer monoliths, including relatively simple preparation processes,abundant monomer availability, and a wide application range of pH, have attracted the attention of chromatographers. Organic polymer monoliths prepared by traditional methods only have macropores and mesopores, and micropores of less than 50 nm are not commonly available. These typical monoliths are suitable for the separation of biological macromolecules such as proteins and nucleic acids, but their ability to separate small molecular compounds is poor. In recent years, researchers have successfully modified polymer monoliths to achieve uniform compact pore structures. In particular, microporous materials with pores of 50 nm or less that can provide a large enough surface area are the key to the separation of small molecules. In this review, preparation methods of polymer monoliths for high-performance liquid chromatography, including ultra-high cross-linking technology, post-surface modification, and the addition of nanomaterials, are discussed. Modified monolithic columns have been used successfully to separate small molecules with obvious improvements in column efficiency.

Preparation of microencapsulatedα-olefin drag reducing polymer used in oil pipeline transportation

Microcapsules containing oil drag-reducing polymer particles were prepared by melting-scattering and condensing of polyethylene wax,in-situ polymerization of urea and formaldehyde,and interfacial polymerization of styrene respectively.The related processes were studied by a molecular dynamics simulation method,and molecular design of microcapsule isolation agent was carried out on the basis of the simulation.The technologies for preparing microencapsulated oil drag-reducing polymer particles were compared and the circulation drag reducing efficiency of the microencapsulated polymer particles was evaluated based on the characterization results and their dissolution properties.Molecular design of a microcapsule isolation agent suggests that a-olefin polymer particles can be stably dispersed in water by using long-chain alkyl sodium salt surfactant which can prevent the agglomeration ofα-olefin polymer particles.The results of simulation of the adsorption process shows that the amount of alkyl sodium salt surfactant can directly affect the stability of microencapsulatedα-olefin polymer particles, and there must be a minimum critical amount of it.After characterization of the morphology by Scanning Electron Microscopy（SEM） and comparison of the static pressure stability,especially the conditions of reaction and technological control of microcapsules with different shell materials,microencapsulation of a-olefin polymer particles with poly-（urea-formaldehyde） as shell material was selected as the optimum scheme,because it can react under mild conditions and its technological process can be controlled in a large range.The relationship of drag reducing rate and dissolving time of microcapsules showed that the formation of microcapsules did not affect the maximum drag reducing rate,and the drag reducing rate of each sample can reach about 35%along with the dissolving time,i.e.microencapsulation did not affect the drag reducing property ofα-olefin polymer.

Preparation and Charcterization of Konjac Superabsorbent Polymer

A superabsorbent polymer was prepared by grafting sodium acrylate （ SA ） onto Konjac flour using potassium persulfate （KPS） and N, N＇-methylene bis acrylamide （ MBA ） as an initiator and crosslinker , respectively. The effect of various preparation conditions on its water absorbency was investigated. When the Konjac Flour content was 3.0g, the acrylic acid （AA） content was 30.0 g, the amount of initiator was 0. 150 g, the neutralization degree of monomer was 85% , the reaction temperature was 60 ℃ and the amount of crosslinker was 0.025 g, the polymer＇s absorbency was 750 times in pure water and 279 times in tap water at ambient temperature. It had also high water retention. The graft efficiency reached 67% . The analyses of FT-IR and SEM indicate that sodium acrylate is grafted on the polysaccharides of Konjac flour.

Preparation and evaluation of duloxetine hydrochloride enteric-coated pellets with different enteric polymers

The main purpose of the present study was to prepare duloxetine hydrochloride(DXH) entericcoated pellets using different enteric polymers. Three layers(drug-loaded layer, barrier layer,and enteric-coated layer) were applied to the inert core pellets, successively. The optimal formulation was manufactured by employing suspension layering method in fluidized bed processor(FBP) with varieties of enteric polymers like Aqoat? AS-LF, Eudragit? L30D55 and HPMCP-HP55. The prepared pellets were measured for physical characterization and the in vitro dissolution profile. Scanning electron microscopy(SEM) was conducted to observe the morphology of pellets, and different kinetic models were applied to analyze the release mechanism of Cymbalta? and home-made pellets. The coating weight gain of enteric-coated layer containing Eudragit? L30D55, Aqoat? AS-LF and HP-55 were determined to be 35%, 26% and 24%, respectively. The similarity factors(f2) of self-made capsules with above polymers and commercially available capsules(Cymbalta?) were above 50 in the dissolution medium of pH 6.8 phosphate buffer solution(PBS). SEM figures showed the smooth surfaces of selfprepared pellets using Eudragit? L30D55 and Aqoat? AS-LF, whereas rough surface was found in the HP-55 pellets at day 0, and an impurity was appearing in the condition of 40 ℃/75% relative humidity for 1 month. In conclusion, the pellets prepared by utilizing Eudragit? L30D55 and Aqoat?AS-LF were the optimal preparations based on the dissolution profile and stability.

Preparation and Application of Polymer Silicate Phosphate Ferric Sulfate Used in High-Viscosity Oil Refining Wastewater Treatment

A new kind of flocculants, named Polymer Silicate Phosphate Ferric Sulfate(PSPFS), was synthesized by ferrous sulfate used as the main material and activated silicic acid as additive. In this paper, High-Viscosity Oil Refining wastewater from Liaohe Petrochemical Corporation was the treatment object. Overall, the in-fluencing factors and synthesis technology conditions of PSPFS were determined by experiments. First of all, the conditions of influencing factors were showed as follows: the mass percent concentration of ferrous sulfate 55%,concentration of sodium silicate 15% , the molar ratio of ferrous sulfate and hydrogen peroxide 1.2:1, oxidation temperature 40 degree Celsius, oxidation time 4 hours, polymerization temperature 60 de-gree Celsius and polymerization time 2 hours. Secondly, the optimal ratios of components were determined by uniform design method. The molar ratio of Fe/Si is 5.0:1, Fe/H2SO4 is 3.2:1, and Fe/P is 18.0:1. At last, the optimal experimental condition was determined as follows: the dosing quantity 200mg/L, pH value 5.5~9, temperature 25~45℃, stirring time 2 min, and standing time 3 min, according to the result of floc-culation experiments with PSPFS. Besides, the result of the comparative experiments showed that the effi-ciency of PSPFS was much better than the reference flocculants.

RECENT ADVANCES IN THE PREPARATION OF MOLECULARLY IMPRINTED POLYMERS VIA CONTROLLED RADICAL POLYMERIZATION TECHNIQUES

Molecular imprinting technique is a simple and efficient method for the preparation of polymer materials (i.e., molecularly imprinted polymers, MIPs) with tailor-made recognition sites for certain target molecules. The resulting MIPs have proven to be versatile synthetic receptors due to their high specific recognition ability, favorable mechanical, thermal and chemical stability, and ease of preparation. Recent years have witnessed significant progress in the synthesis and applications of MIPs. This review focus on the recent developments and advances in the preparation of MIPs via various controlled radical polymerization techniques.

Preparation of adhesive resveratrol micelles and determination of drug content

Objective:Resveratrol polymer micelles with tissue adhesion were prepared and the content of resveratrol in the micelles was determined by HPLC.Method:The micelle adhesion experiment was carried out by polylysine orifice plate experiment and small animal fluorescence imaging method,and the micelle prescription was optimized to obtain resveratrol micelles with good adhesion.The separation was performed on a Shiseido SPOLAR C18 column(150 mm×4.6 mm,5μm)with methanol-water(42:58)as the mobile phase.The flow rate was 1.0 mL·min^(-1),the detection wavelength was 305 nm,the column temperature was 35℃,and the injection volume was 10μL.Results:Resveratrol micelles prepared with F127 alone had the best adhesion.The peak area and concentration of resveratrol had a good linear relationship in the concentration range of 10~200μg/mL(r=0.9996).The specificity,precision,recovery and stability all met the methodological requirements.Conclusion:In this experiment,resveratrol micelles with tissue adhesion were successfully prepared,and a method for the determination of resveratrol content in micelles was established.The method is accurate,rapid and simple.

Preparation technologies for polymer composites with high-directional thermal conductivity:A review

With the rapid development of science and technology,electronic devices are moving towards miniaturization and integration,which brings high heat dissipation requirements.During the heat dissipation process of a heating element,heat may spread to adjacent components,causing a decrease in the performance of the element.To avoid this situation,the ability to directionally transfer heat energy is urgently needed.Therefore,thermal interface materials(TIMs)with directional high thermal conductivity are more critical in thermal management system of electronic devices.For decades,many efforts have been devoted to the design and fabrication of TIMs with high-directional thermal conductivity.Benefiting from the advantage in feasibility,low-cost and scalability,compositing with thermal conductive fillers has been proved to be promising strategy for fabricating the high-directional thermal conductive TIMs.This review summarizes the present preparation technologies of polymer composites with high-directional thermal conductivity based on structural engineering of thermal conductive fillers,focusing on the manufacturing process,mechanisms,achievements,advantages and disadvantages of different technologies.Finally,we summarize the existing problems and potential challenges in the field of directional high thermal conductivity composites.

Preparation and Properties of PBXs Based on FOX-7 in Controlled Fragmentation Warhead Application

Polymer bonded explosive(PBX)formulations were successfully prepared in the laboratory scale containing 1,1-diamino-2,2-dinitroethene(FOX-7)and hexogen(RDX)as brisant high explosives and different binder types of polyurethane(PU)based on glycidyl azide polymer(GAP) and hydroxyl-terminated polybutadiene(HTPB) as an energetic and inert polymeric binder respectively.Casting technique was used for the preparation of different PBX formulations based on FOX-7/RDX and PU(GAP/HTPB)with 14% binder.The sensitivity to different initial impulses and performance characteristics of the explosive and lethal zone of the tested controlled fragmentation warhead by the fragmentation warhead assessment test(arena test)were studied,in which the arena test was carried out with a controlled fragmentation warhead made from Ck45 steel,with dimensions(100 mm length,30 mm outer diameter and 3 mm thickness).Results show that PBXGF4 has lower sensitivity to impact and heat than those of PBXGR4 by 188.4% and 3.2% respectively.Its friction sensitivity is the same as that of PBXGR4.It has better performance,in which detonation velocity increases by 2.1% and brisance increases by 0.5% when compared with those of PBXGR4.It was concluded that PBXGF4 which based on FOX-7 bonded with PU/GAP matrix has good characteristics as PBX,specially in the sensitivity to impact and can be applied for replacing PBXs based on RDX in the advanced PBXs for low sensitive fragmentation warheads.

Preparation and Characterization of PEDOT Films for NO_2 Gas Sensors

A novel NO_2 gas sensor was constructed by depositing poly(3,4-ethylenedioxyphioen)(PEDOT)films on the surface of interdigital electrodes.The conducting polymer PEDOT films were prepared by chemical synthesis.The conductibility tests indicated that the resistances of PEDOT films increased with the increase of NO_2 concentration.The mechanism of increasing resistance of PEDOT films could be suggested that electrons of NO_2-gas acted as the electron donor to p-type semiconductor of PEDOT with the consequence of reducing the numbers of holes in the PEDOT and the increase resistance of the thin film.The linear relationship between the shift of resistance and the concentration of NO_2 existed in a range from 10μg/g to 30μg/g.The sensitivity of PEDOT films to NO_2 was 10Ω/10^(-6).

Preparation and Recipe Optimization of Water-based Architectural Heat Insulation Coatings

Water-based architectural heat insulation coatings were studied to overcome the drawbacks of conventional inorganic silicate heat insulation coatings. The heat insulation coatings were prepared with the method of mechanical agitation when the mixed organic polymer emulsions were used as binder of the coatings and the mixed heat insulating aggregates were applied as powder, and some assistants were also added. Water temperature difference in the plastic container, which was coated with heat insulation coatings, represented the heat-insulating property of the coatings. The influences of components of mixed polymer emulsion, mass ratio of polymer emulsion to powder, particle size of heat insulating aggregates, added amount of air entraining admixture and the match of thickeners on the properties of the coatings were studied. The experimental results show that the heat insulation coatings with good finishing, heat-insulation property and artificial weathering can be prepared when the binder is composed of 66.92% styrene-acrylic emulsion, 16.59% elastic emulsion and 16.49% silicone-acrylic emulsion, the mass ratio of polymer emulsion to powder is 0.45, the particle size of heat insulating aggregates is in the rang of 200 and 250 mesh size, the added amount of sericite is 15%, and the added amount of air entraining admixture is in the range of 1.0% and 1.5% and the thickeners are the mixtures of ASE-60 and RM-5000.

Preparation and Application of Chitosan-based Polyelectrolyte Complex Materials: An Overview

Chitosan,a renewable,non-toxic,and natural cationic polyelectrolyte,can be combined with many anionic polyelectrolytes(such as sodium alginate,hyaluronic acid,xylan,and gelatin)via electrostatic forces to form chitosan-based polyelectrolyte composites under certain conditions.This review summarizes various methods of preparing chitosan-based polyelectrolyte composites and analyzes their applications in clinical medicine and agriculture,as well as pharmaceutical,tissue,food,environmental,and textile engineering fields.The future development direction and potential of chitosan-based polyelectrolytes are also discussed.

Preparation and characterization of conducting polymer-coated thermally expandable microspheres

The thermally expandable microspheres（TEMs） were prepared via suspension polymerization with acrylonitrile（AN）, methyl methacrylate（MMA） and methyl acrylate（MA） as monomers and n-hexane as the blowing agent. Meanwhile, a novel type of functional and conductive thermal expandable microsphere was obtained through strongly covering the surface of microsphere by conductive polymers with the mass loading of 1.5%. The optimal conditions to prepare high foaming ratio and equally distributed microcapsules were investigated with AN-MMA-MA in the proportion of 70%/20%/10%（m/m/m）, and 25 wt% of n-hexane in oil phase. The further investigation results showed that the unexpanded TEMs were about 30 μm in diameter and the maximum expansion ratio was nearly 125 times of original volume. The polypyrrole（PPy） was smoothly coated on the surface of the TEMs and the expansion property of PPy-coated TEMs was almost the same as the uncoated TEMs. Moreover, the structure and expanding performance of TEMs and PPy-coated TEMs were characterized by scanning electron microscopy（SEM）, laser particle size analyzer and dilatometer（DIL）.

Scalable preparation and direct visualization of cyclic polymers via self-folding cyclization technique

Cyclic polymers exhibit distinct properties compared with their linear counterparts due to the lack of chain ends.However,the scalable synthesis of cyclic polymers remains a major challenge,especially for ring-closure method.Herein,we report a novel strategy for large-scale preparation of cyclic polymers,which relies on the prior self-folding of anthracene-telechelic amphiphilic random copolymers(poly((oligo(ethylene glycol)acrylate)-co-(dodecyl acrylate)),P(OEGA-co-DDA))into single-chain polymeric nanoparticles(SCPNs)in water.Subsequent ultraviolet(UV)-induced cyclization occurs in the hydrophobic nano-domain.The formation of SCPNs leads to a shortened distance between the end groups of the linear precursors and spatially separated cyclization loci,and significantly enhances the efficiency of UV-induced cyclization.This self-folding technique permits access to the synthesis of cyclic polymers not only with high molecular weights(M_(n)>10^(5) g/mol),but also in a decent scale(40 g/L),breaking through the limitations of ring-closure method.Furthermore,the dense pendants of the copolymers can magnify the macromolecules by increasing the mass density along the backbones,thus making the polymers more readily detectable by the microscopy.The transmission electron microscopy(TEM)and atomic force microscopy(AFM)images allow us to observe the topological structures directly and provide crucial evidence to confirm the cyclization.

Improving the performance of polymer solar cells by adjusting the crystallinity and nanoscale phase separation

In this paper, we report a high-perfornmnce P3HT/PCBM bulk-heterojunction solar cell with a power conversion efficiency of 4.85% fabricated by adjusting the polymer crystallinity and nanoscale phase separation using an ultrasonic irradiation mixing approach for the polymer. The grazing incidence X-ray diffraction, UV/Vis spectroscopic, and atomic force microscopic measurement results for the P3HT/PCBM blend films reveal that the P3HT/PCBM film fabricated by ultrasonic irradiation mixing of the P3HT and PCBM solutions for 10 min has a higher degree of crystallinity, a higher absorption efficiency, and better phase separation, which together account for the higher charge transport properties and photovoltaic cell performance.