Preparation of Poly-α-Olefin Microcapsule Particles Coated with Polyurethane as a Drag Reducer Based on Interface Polymerization

The molecular behavior of polyurethane(PU)coating materials during the surface adsorption of poly-α-olefin as a drag reducing polymer was explored by a molecular dynamics simulation.Three different PU capsule wall materials were synthesized using two reaction monomers,and a poly-α-olefin/PU drag reducer microcapsule was prepared based on interface polymerization.The structure,morphology,thermal stability,compressive strength,and drag reduction performance of the microcapsules were characterized and compared.The results showed that a non-bonding interaction induced the adsorption of the PU coating material,poly-α-olefin and PU then fused at the interface,and the PU coating material was embedded into the inner grooves of poly-α-olefin in the form of a local mosaic,thereby forming a stable core–shell structure.The morphological characterization indicated that PU and poly-α-olefin could form microcapsule structures.The thermal decomposition temperature of the microcapsule was dependent on the type of capsule wall material.The microcapsule structure had a slight effect on poly-α-olefin drag reduction.The system enabled poly-α-olefin to exist in powdered particles through microcapsulation,and had a good dispersion effect that facilitated storage and transport processes.The method effectively inhibited the accumulation and bonding of poly-α-olefin at room temperature.

In-situ polymerized PEO-based solid electrolytes contribute better Li metal batteries:Challenges,strategies,and perspectives

Polyethylene oxide(PEO)-based solid polymer electrolytes(SPEs)with good electrochemical stability and excellent Li salt solubility are considered as one of the most promising SPEs for solid-state lithium metal batteries(SSLMBs).However,PEO-based SPEs suffer from low ionic conductivity at room temperature and high interfacial resistance with the electrodes due to poor interfacial contact,seriously hindering their practical applications.As an emerging technology,in-situ polymerization process has been widely used in PEO-based SPEs because it can effectively increase Li-ion transport at the interface and improve the interfacial contact between the electrolyte and electrodes.Herein,we review recent advances in design and fabrication of in-situ polymerized PEO-based SPEs to realize enhanced performance in LMBs.The merits and current challenges of various SPEs,as well as their stabilizing strategies are presented.Furthermore,various in-situ polymerization methods(such as free radical polymerization,cationic polymerization,anionic polymerization)for the preparation of PEO-based SPEs are summarized.In addition,the application of in-situ polymerization technology in PEO-based SPEs for adjustment of the functional units and addition of different functional filler materials was systematically discussed to explore the design concepts,methods and working mechanisms.Finally,the challenges and future prospects of in-situ polymerized PEO-based SPEs for SSLMBs are also proposed.

In-situ interfacial passivation and self-adaptability synergistically stabilizing all-solid-state lithium metal batteries

The function of solid electrolytes and the composition of solid electrolyte interphase(SEI)are highly significant for inhibiting the growth of Li dendrites.Herein,we report an in-situ interfacial passivation combined with self-adaptability strategy to reinforce Li_(0.33)La_(0.557)TiO_(3)(LLTO)-based solid-state batteries.Specifically,a functional SEI enriched with LiF/Li_(3)PO_(4) is formed by in-situ electrochemical conversion,which is greatly beneficial to improving interface compatibility and enhancing ion transport.While the polarized dielectric BaTiO_(3)-polyamic acid(BTO-PAA,BP)film greatly improves the Li-ion transport kinetics and homogenizes the Li deposition.As expected,the resulting electrolyte offers considerable ionic conductivity at room temperature(4.3 x 10~(-4)S cm^(-1))and appreciable electrochemical decomposition voltage(5.23 V)after electrochemical passivation.For Li-LiFePO_(4) batteries,it shows a high specific capacity of 153 mA h g^(-1)at 0.2C after 100 cycles and a long-term durability of 115 mA h g^(-1)at 1.0 C after 800 cycles.Additionally,a stable Li plating/stripping can be achieved for more than 900 h at 0.5 mA cm^(-2).The stabilization mechanisms are elucidated by ex-situ XRD,ex-situ XPS,and ex-situ FTIR techniques,and the corresponding results reveal that the interfacial passivation combined with polarization effect is an effective strategy for improving the electrochemical performance.The present study provides a deeper insight into the dynamic adjustment of electrode-electrolyte interfacial for solid-state lithium batteries.

SYNTHESIS AND CHARACTERIZATION OF POLYPROPYLENE/MONTMORILLONITE NANOCOMPOSITES VIA AN in-situ POLYMERIZATION APPROACH

Polypropylene/montmorillonite (PP/MMT)nanocomposites were prepared by in-situ polymerization using aMMT/MgCl_2/TiCl_4-EB Ziegler-Natta catalyst activated by triethylaluminum(TEA). The enlarged layer spacing of MMT wasconfirmed by X-ray wide angle diffraction (WAXD), demonstrating that MMT were intercalated by the catalyst components.X-ray photoelectron spectrometry (XPS) analysis proved that TiCl_4 was mainly supported on MgCl_2 instead of on the surfaceof MMT The exfoliated structure of MMT layers in the PP matrix of PP/MMT composites was demonstrated by WAXDpatterns and transmission electron microscopy (TEM) observation. The higher glass transition temperature and higher storage modulus of the PP/MMT composites in comparison with pure PP were revealed by dynamic mechanical analysis (DMA).

Preparation of Polysulfonamide/ZnO Nanocomposite by In-Situ Polymerization

Polysulfonamide/zinc oxide(PSA/ZnO) nanocomposite films with w(ZnO)=0.5% were prepared by in-situ polymerization based on 4,4′-diaminodiphenylsulfone and terephthaloyl chloride in the common solvent N,N-Dimethylacetamide(DMAc). Atomic force microscopy (AFM) was employed to observe the microstructure of the composite film. The thermal property was investigated by TGA and mechanical property was characterized by DXLL-1000 electromechanical material testing machine. The results showed that the breaking strength of the film containing 0.5% ZnO was great enhanced. The average size of ZnO particles was below 100 nm. The introduction of ZnO as nano filler in PSA react as UV shield effect and make the composite mechanical property improved.

CHANGES OF STRUCTURE AND PROPERTIES OF POLY (ETHYLENE TEREPHTHALATE) CAUSED BY IN-SITU POLYMERIZATION OF PYRROLE

Conductive polymer composites based on crystalline polymer matrix have been prepared by using an in-situ polymerization process of pyrrole in amorphous poly （ethylene terephthalate） （PET） film. The DSC and WAXD measurement and SEM observation show that liquid-induced crystallization of PET matrix has occurred during the preparation of composite films. Depending upon the equilibrium degree of swelling and crystallinity, the limited depth of penetration of pyrrole molecules results in a skin-core structure of the composite film. The skin layer containing charge transfer intercalated polypyrrole has a surface resistance of 3.5×10;Ω. Rigid and heat-resistant polypyrrole molecules formed in PET film increase the tensile modulus and, especially, the rigidity of PET at elevated temperatures. However, they decrease the tensile strength and elongation at break, and impair the thermal ductility of PET.

Research on microcapsules of phase change materials

Microcapsule technology is a kind of technology wrapping the solid or liquid into minute-sized particles within the field of micrometer or millimeter with film forming materials. This thesis introduces microcapsule technology of phase change materials and its main functions and the structural composition, preparation methods and characterization technology of microcapsule of phase change materials. The microcapsule of phase change materials is small in size and its temperature remains unchanged during the process of heat absorption and heat release. It is of great value in research and application prospect due to these characteristics.

Synthesis and Characterization of Ethylenediamine Tetraacetic Acid Tetrasodium Salt Loaded in Microcapsules with Slow Release Properties

The microcapsules with cores of ethylenediamine tetraacetic acid tetrasodium salt(Na4-EDTA)and walls of polyurea were synthesized via an interfacial polycondensation reaction with 2,4-tolylene diisocyanate as an oil-soluble monomer and diethyl triamine as a water-soluble monomer.Various manufacturing parameters,including the amount of emulsifier,agitation speed,stirring time and ratios of the wall materials to core materials,were altered to optimize process variables during the synthesis of microcapsules,and the effects of these parameters on the characteristics of the microcapsules were examined.The structure,morphology,mean particle size and size distribution were characterized by optical microscope and scanning electron microscopy(SEM),showing that the mean diameter of optimal microspheres was approximately 6μm,and microcapsules were spherical.In vitro release of Na4-EDTA from these microcapsules was performed in distilled water.Under the optimal preparation conditions, the Na4-EDTA release profiles were biphasic with a burst release followed by a gradual release phase.After an initial burst,a continuous Na4-EDTA release was up to 5-7 days.The optimal synthesis conditions for the microcapsules with stable,good morphology and good controlled-release properties were as follows:emulsifier Span-80 10% (by mass),agitation speed 900 r·min1,stirring time 30 min,and the ratio of the wall materials to core materials 0.15.

Improving the Dispersibility of Poly(urea-formaldehyde) Microcapsules for Self-Healing Coatings Using Preparation Process

Poly(urea-formaldehyde)(PUF)microcapsules were prepared by in-situ polymerization with four different pro-cesses in this paper.The chemical composition,surface morphology,particle size distribution,and thermal sta-bility were characterized by FTIR,SEM,particle size analyzer,and TGA,respectively.The results demonstrated that the agglomeration of the PUF microcapsules was related to the agglomeration of the emulsion particles caused by the changes of emulsion interface during the shell polymerization.Due to the slow deposition of the shell material,the PUF microcapsules with the core-shell structure prepared by the process with ammonium chloride as the last additive showed good dispersibility with an average diameter of 6.36μm,high core content of 71.3 wt%,and high yield of 61.3 wt%.The PUF microcapsules had good thermal stability below 216?C.The PUF microcapsules could be uniformly dispersed in the epoxy coating in a single form.The epoxy coating with 2 wt%PUF microcapsules showed good self-healing property,and the service life of the coating was about doubled.

Effects of Processing Conditions on the Properties of Epoxy Resin Microcapsule

In order to improve the healing performance and increase the service life of the polymer matrix composites, microcapsules were prepared by interracial polymerization process with urea formaldehyde resin and epoxy resin E-51 as the wall material and core material separately. The effects of core/shell mass ratio and emulsifier on the distribution, topography and encapsulation rate of microcapsules were investigated. By optimizing the conditions, microcapsules with little particle size, well dispersion and compact surface were prepared. The distribution, topography, stability and compositions of the microcapsules were characterized using Nano-2s, optical microscope, scanning electron microscopy, thermal analysis and Fourier transform infrared spectroscopy. The osmosis performance of the microcapsules was evaluated. The experimental results showed that the ratio of core/shell materials （1：1） and 1% DBS as emulsifier were optimum preparation conditions and the encapsulation rate was 62.5%. The microcapsules can be synthesized successfully with mean diameter 548.6 nm and exhibit a good chemical stability below 225 ℃. The FTIR result indicated that urea-formaldehyde resin was formed and the core materials were successfully encapsulated in urea-formaldehyde shell. Osmosis performance evaluation showed that the microcapsules were well coated and slowly osmosed.

Preparation of Microcapsules Containing Water Droplets Stabilized with Solid Powder and Application to Blowing Agent

We have tried to prepare the microcapsules containing water droplets stabilized with solid powder by utilizing the (W/O)/W emulsion. The water droplets as core material were stabilized in the monomer droplets with titanium dioxide (TiO2) as a particulate surfactant. Before adding the TiO2 powder into the monomer phase, the powder was modified with triethoxyvinylsilane to adjust the degree of hydrophobicity and to promote adhesion on the interface between the inner water phase and the monomer phase in the (W/O) emulsion. It was investigated how the degree of hydrophobicity of the TiO2 powder affected the stability of water droplets in the (W/O) emulsion and the (W/O) droplets in the (W/O)/W emulsion. Moreover, the microcapsule diameters were measured before and after the expansion operation where the water droplets microencapsulated were applied as a blowing agent. The expansion ratio was increased with increase in the stability of the water droplets and the amount of water microencapsulated.

Crystalline Morphology and Crystallization Characteristics of In-situ Blends of Anionic Polyamide 6 with Noncrystallizable Semiaromatic Polyamide Copolymer

A noncrystallizable semiaromatic polyamide copolymer（NSAP） was dissolved in molten caprolactam, and PA6/ NSAP blends were produced in-situ via the anionic ring-opening polymerization of caprolactam. The presence of a single loss tangent（tanS） peak measured by means of dynamic mechanical analysis（DMA） proves the miscibility between PA6 and NSAP in the blends. It was found that there existed drastic changes in the crystallographic form and crystallization kinetics for the in-situ blends, e.g. , when 20% NSAP was added, nearly all crystallites existed in the ,y form and the crystallization could hardly occur upon cooling even at a rate of 2.5 ℃/min. Moreover, cold crystallization appears during the subsequent heating, and its melting point is 40 ℃ lower than that of the virgin system. On the other hand, the size of the spherulites only decreases modestly. It is suggested that the introduction of irregular stiff segments originated from NSAP into PA6 macromolecule chain, which resulted from transamidation during the polymerization play a dominant role in the drastic change of crystallization kinetics and the resultant morphology of the in-situ blends.

Preparation of Well-shaped Microcapsule Immobilizing Inorganic Nanoparticles

一个灵巧、有效的方法通过把分裂成原子的乳化途径经由 toluene-2,4-diisocyanate 和 H2O 的界面聚合在 polyurea 为金属氧化物 nanoparticles 的微封装被开发了。结果的微囊是有直径从 2 ～ 6 μ m .Thermogravimetry (TG )的塑造得好、一致的范围，微分扫描热量测定(DSC ) 曲线表明微囊显示出好热稳定性(在 245 ° C 下面观察的没有分解) 。而且，微包含的 TiO2 为相片被用作有效催化剂甲基橙的催化降级。而且，使不能调动的 TiO2 的光催化能被把紫外吸收代理人介绍给微囊的墙提高。

Effect of Core Material on Breaking Behavior of Self-Bursting Microcapsules

Self-bursting microcapsules, which retain their shape when suspended in water but burst quickly after the water evaporates, were proposed in a previous report. In this report, the effect of core materials on the bursting mechanism was studied. Five kinds of solvents were used as core materials, microencapsulated with polyurethane via an interfacial polymerization method. It was found that the self-bursting ratio was proportional to the measured dielectric constant of the core material. Thus, the solvents with a higher dielectric constant had an effect on the wall material to a greater extent. Furthermore, the self-bursting ratio was able to be predicted using the “organic conceptual diagram.”

Microencapsulation of Chlorocyclophosphazene by Interfacial Polymerization

A polyurea-chlorocyclophosphazene microcapsule flame retardant is prepared by an interfacial polymerization process using 2,4-toluene diisocyanate (TDI) and hexanediamine as the raw materials. TG tests show that the thermal decomposition temperature of chlorocyclophosphazene in microcapsule obviously rises. The flame retardancy of HDPE/chlorocyclophosphazene in microencapsules is better than that of HDPE/chlorocyclophosphazene. Mechanical properties of HDPE/chlorocyclophosphazene microencapsule turn out to be superior to those of HDPE/chlorocyclophosphazene.

A NOVEL EOR POLYMER (Ⅱ)——INVESTIGATION ON IN-SITU GELATION OF SMRF SYSTEM IN BEREA CORE

In-situ gelation of aqueous sulfomethylated resorcinol formaldehyde (SMRF) system inBerea core has been investigated. Two sets of displacement experiments were conducted with thissystem (containing 5% NaCl, 0. 036% CaCl_2. 2H_2O). The brine permeabilities of the coreswere reduced significantly from about 600 to 0.1 md. The in-situ gelation in Berea core occurreda little bit earlier than gelation anticipated from bulk test in the experiments. The gel time waseasier to control at initial pH between 6 and 8. During injection of SMRF system, the apparentviscosity was less than 1 mPa·s at 41℃.

In situ polymerization preparation and mechanical properties of nanocomposites based on PA10T/10I-block-PEG copolymer and graphene oxide

Poly(decamethylene terephthalamide/decamethylene isophthalamide)-block-polyvinyl alcoho)(PA10 T/10 IPEG) copolymer/graphene oxide(GO) composites were prepared via in-situ melt polymerization and two different nano-filler addition approaches were compared. The relationship between the micro-structure and performance of the elastomer composites prepared by one-step and two-step methods was explored. The results show that the two-step method significantly promoted the dispersion of the GO in a polymer matrix, and facilitated the grafting of more hard molecular chains. Thus, the elastic modulus and tensile strength of the nanocomposite have been significantly improved by the presence of GO. This was because of the strong interaction between the functional groups on the surface of the GO and the hard molecular chains. This would be also be favorable to load transfer across the interface. Additionally, the elongation at the break of composites increased by 10% with the addition of a small amount of GO(0.2% wt). This is because hard domains tend to be enriched on the surface of GO in composites and act as a lubricating layer at the interface between the GO and matrix, leading to increased deformation ability. This work provides an effective strategy to prepare elastomer composites with high strength and toughness.

Effects of Surface Modifi cation on the Properties of Microcapsules for Self-healing

Poly（urea-formaldehyde）（UF） microcapsules with epoxy resin E-51 as core material used as self-healing materials were prepared by interfacial polymerization method. The surface of UF microcapsules was modifi ed by γ-（2,3-epoxypropoxy） propytrimethoxysilane（KH-560）. The interfacial interactions between UF microcapsules and KH-560 were studied by Fourier transform infrared spectroscopy（FTIR） and X-ray photoelectron spectrometric analysis（XPS） of microcapsules. The surface topography of microcapsules was characterized by scanning electron microscopy（SEM）. The thermal stability and mechanical properties were evaluated. FTIR and XPS results showed that there were physical and chemical combinations between the silicon coupling agent and the microcapsules surface. The thermal stability and mechanical property analysis showed that the addition of KH-560 could greatly improve the thermal stability, tensile property and elastic property. SEM results indicated that the addition of KH-560 could improve the bonding between the surface of microcapsules and resin matrix and improve the ability of self-healing.

Preparation and Characterization of Poly(divinylbenzene) Microcapsules Containing Octadecane

Poly(divinylbenzene) (PDVB) microcapsules containing octadecane (OD) (PDVB/OD) used as heat storage material were synthesized by suspension polymerization at 70 Microencapsulation, Microcapsule, Heat Storage Material, Octadecane, Suspension Polymerization, Poly(Divinylbenzene)C using benzoyl peroxide and polyvinyl alcohol as initiator and stabilizer, respectively. Thermal properties and stability of PDVB/OD microcapsules were determined using differential scanning calorimeter (DSC) and thermogravimetric analyzer. The morphology and structure of microcapsules were characterized by optical microscope, scanning electron microscope and fourier transform infrared spectrophotometer. From DSC analysis, the melting temperature of encapsulated OD (28oC) was almost the same as that of bulk OD (30oC) while it was quite different in the case of the solidification temperature (19oC and 25oC for encapsulated and bulk OD, respectively). The latent heats of melting (184.0 J/g-OD) and solidification (183.2 J/g-OD) of encapsulated OD were reduced from those of bulk OD (241.7 and 247.0 J/g, respectively). However, the prepared PDVB/OD microcapsules are able to be used for heat storage applications.