Preparation Of Poly Research Articles

Preparation of poly(ε-caprolactone) based composites through multistage biaxial-stretching extrusion with excellent oxygen and water vapor barrier performance

In this paper, the poly(ε-caprolactone)/glycerol tristearate (PCL/C18) composites were prepared through multistage biaxial-stretching extrusion, and the hydrophobic C18 was transformed significantly from small spheres into sheet-like structures. The hydrophobicity of the material was enhanced, and the diffusion path for the penetration of the small molecules was significantly increased, resulting in an improvement in the oxygen and water vapor barrier performance. Compared with conventional PCL/C18 blends with the same C18 content (10%), the oxygen and water vapor barrier performance of the modified composites further increased by 63.7% and 39.6%, respectively. Furthermore, when the relative humidity (RH) increased from 50% to 90%, the water vapor permeability (WVP) of sample C18-6 increased slightly from 6.94 × 10−14 g·cm·cm−2·s−1·Pa−1 to 7.66 × 10−14 g·cm·cm−2·s−1·Pa−1, exhibiting excellent stability to high humidity. Meanwhile, our materials have good biodegradability and mechanical properties, which can be well applied in the food and medicine packaging fields.

Preparation of poly(lactic acid)-based shape memory polymers with low response temperature utilizing composite plasticizers

Preparation of poly(lactic acid)-based shape memory polymers with low response temperature utilizing composite plasticizers

Preparation of poly(butylene succinate) vitrimer with thermal shape stability via transesterification reaction

AbstractPoly(butylene succinate) (PBS) refers to a high‐performance biodegradable polymer employed to substitute petroleum polymers that cause environmental issues. However, PBS exhibits the defect of flowing above the melting point and rapid dripping for its poor melt strength. Accordingly, this study proposed a novel method to fabricate PBS vitrimer by exploiting reactive extrusion technology to mix diepoxide with PBS and then by employing zinc acetate as a catalyst to crosslink the PBS. Therefore, after the reaction extrusion blending, the blend still has a lower viscosity and high processing performance; in the subsequent curing process, the polymer undergoes a transesterification reaction and the viscosity increases. Via transesterification to form a cross‐linked network, the storage modulus, and loss modulus of PBS vitrimer at 140°C reach 55,800% and 3500% of pure PBS, respectively. At this time, the crystallinity of PBS vitrimer is still as high as 56.9% (The crystallinity of pure PBS is 47.4%). And the shape stability of PBS at high temperatures was significantly improved. Moreover, PBS vitrimer could still be reshaped after the cross‐linking process. This study proposed a facile method to produce PBS materials exhibiting high thermal shape stability.

Preparation of Poly(arylamino‐quinone) Polymer and Its Electrochemical Properties as a Cathode Material for Lithium Ion Battery

AbstractThe exploration of organic materials for electrochemical energy storage has attracted much attention, and our studies focus on quinone‐based polymer that is employed as the electrode materials for lithium‐ion batteries. In this article, two poly(arylamino‐quinone) polymers are prepared by Michael addition polymerization reaction. The constructed poly(arylamino‐quinone) polymers contained the quinone units in arylamine‐linked conjugated skeleton, which possess the branched molecular structure for poly (tris(4‐aminophenyl)amine‐benzoquinone) (PAQ1) and the linear molecular structure for poly (p‐phenylenediamine‐benzoquinone) (PAQ2), respectively. As explored as the organic cathode materials for lithium‐ion batteries, PAQ1 with granular morphology exhibits the discharge capacity of 429.6 mAh. g−1 in the first cycle and the improved average discharge potential. Also, it shows that the stable cycling stability after the capacity attenuation in the initial cycles and the high current rate performances as comparing to PAQ2. It can be ascribed to the introduction of triphenylamine unit in polymer and the assembled granular morphology, which contributes to improved electrochemical performances for PAQ1.

Preparation of poly(carbazole-TEMPO) electrode and its electrochemical performance

Carbazole monomer with a side chain nitroxyl radical 4-(9H-carbazol-9-yl)acetyl-oxy-2,2,6,6-tetramethylpiperidin-1-yloxy (Cz-TEMPO), was designed and synthesized successfully. The corresponding polymer electrode poly(carbazole-TEMPO) (PCz-TEMPO) has been electrochemically prepared in CH3CN solution with different supporting electrolytes. PCz-TEMPO film was homogeneously dispersed on the surface of Pt electrode and characterized by FTIR, SEM, XPS and element mapping. The electrocatalytic performances of PCz-TEMPO electrode for oxidation of benzyl alcohol were investigated by cyclic voltammetry and in situ FTIR spectroscopy. Tetrabutylammonium tetrafluoroborate (TTFB) was the most efficient supporting electrolyte for preparing PCz-TEMPO electrode among the four supporting electrolytes. In addition, the electroactivity of PCz-TEMPO-TTFB electrode remained 94.6% after 100 scanning cycles in 0.1 M NaClO4/CH3CN solution.

Preparation of Poly(acrylic acid) ‐Boron Nitride Composite as a Highly Efficient Adsorbent for Adsorptive Removal of Heavy Metal Ions

AbstractThe poly(acrylic acid)‐boron nitride composite was prepared by radical initiated polymerization in situ with N,N′‐methylenebisacrylamide (MBAA) as a crosslinker and potassium persulfate (KPS) as an initiator and the structure of poly(acrylic acid)‐boron nitride were characterized by Fourier Transform infrared spectroscopy (FT‐IR), scanning electron microscope (SEM). The ability of poly(acrylic acid)‐boron nitride as adsorbent for adsorptive removal of heavy metal ion from aqueous solutions was investigated. The effects of poly(acrylic acid)‐boron nitride dosage, pH, adsorption time, initial metal ion concentration and temperature on adsorption efficiency were also studied. Kinetics data followed best by pseudo‐second‐order model with the correlation coefficient (R2) of 0.997. The equilibrium adsorption data was well fitted to Langmuir isotherm models for Cu(II). The adsorption capacities (qmax) of poly(acrylic acid)‐boron nitride composite for Cu(II) was 46.72 mg/g. The results of thermodynamic equilibrium constant and the Gibbs free energy indicated the spontaneous nature of the adsorption process.

Facile Preparation of Poly(ionic liquid)s-zinc Halide Composite Toward Highly Efficient Conversion of CO<sub>2</sub> into Cyclic Carbonates

Facile Preparation of Poly(ionic liquid)s-zinc Halide Composite Toward Highly Efficient Conversion of CO<sub>2</sub> into Cyclic Carbonates

Preparation of poly(sodium 4-styrene sulfonate) grafted magnetic chitosan microspheres for adsorption of cationic dyes

A novel adsorbent with high adsorption capacity to remove cationic dyes was synthesized. Sodium 4-styrene sulfonate (SSS) was grafted polymerization on the surface of magnetic chitosan microspheres via -NH2/S2O82− surface initiating system, obtaining MCS-g-PSSS microspheres. The grafted microsphere was characterized by Fourier transforms infrared spectroscopy, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, vibration sample magnetometer and the Brunauer-Emmett-Teller. Cationic dyes were adsorbed by MCS-g-PSSS and methylene blue(MB) was acted as a typical example. The adsorption performance was explored by varying experimental conditions. The results showed the maximal adsorption capacity was 989 mg/g at pH 1 at 25 °C. The pseudo-second order model was found to be applicable for the adsorption kinetics. The adsorption capacity increased with rising temperature and it decreased owing to adding of ions. The adsorption isotherms were the best fitted by Langmuir. MCS-g-PSSS for MB showed high adsorption capacity due to the strong electrostatic interactions and π-π stacking, which was explained by FTIR and XPS and was verified by DFT calculations. The degree of adsorption spontaneity increased with rising the temperature. The grafted MCS-g-PSSS microspheres had high adsorption capacity for various kinds of cationic dyes and excellent for remove MB in the aqueous solution.

Preparation of Poly Lactic-Co-Glycolic Acid-Based Implant Biomaterials and Its Adoption in Restoration of Periodontal Missing Teeth

As a commonly used macrolide antibiotic, azithromycin (AZM) has achieved favorable results in the treatment of periodontitis. However, due to the complex environment of the oral cavity, the time of action of topical medication is limited. In this study, AZM-poly lactic-co-glycolic acid (PLGA) microspheres were prepared by the emulsion-solvent evaporation method, whose morphology was observed by scanning electron microscopy. The AZM-PLGA microspheres of different specifications were obtained by using a paddle agitator and a homogenizing agitator, respectively. For the above two different specifications of AZM-PLGA microspheres, the mass ratios of AZM and PLGA were adjusted to 10:100, 15:100, 20:100, and 30:100, respectively. After the mechanical analysis of the microspheres, the slurry-type AZM-PLGA microspheres were taken as the positive control, and the critical defect model of alveolar bone was implanted in New Zealand white rabbits. Then, CT imaging of alveolar bone tissue was obtained at different time points after surgery. Plasma microspheres (20:100) were selected as the implant materials for the restoration of missing teeth in patients with periodontitis. After the test, the results showed that the AZM-PLGA microspheres obtained by the paddle agitator had relatively smaller particle size and smoother surface. The initial release rate of slurry microspheres of different quality was relatively fast, the follow-up rate was relatively stable, and the dosage ratio should not be more than 20%. Slurry microspheres had stronger mechanical properties compared with homogenized microspheres. The osteogenesis observation residues of slurry microspheres with different mass ratios were 15%, 23%, 37%, and 26% at 2–16 weeks, respectively, showing a relatively stable degradation mode. After the five patients with periodontitis participated in the restoration with the use of plasma microspheres (20:100) implants, the periodontal condition was greatly improved. During the observation period, all implants were not loosened and there was no discomfort during percussion.

Preparation of poly(N-vinyl caprolactam) with various end groups using chain transfer agents and evaluation of their effects on kinetic hydrate inhibition

Poly(N-vinylamide) derivatives were synthesized to improve the performance of kinetic hydrate inhibitors (KHIs). In this work, we synthesized poly(N-vinylformamide) (PNVF) and poly(N-vinylcaprolactam) (PVCap) by free radical polymerization with several commercial chain transfer agents (CTAs), which afforded a few thousand Mn. The structures of synthesized PNVF and PVCap were then investigated by 1H NMR and MALDI-TOF/MS spectrograms. KHI properties of the synthesized PNVF and PVCap polymers were also evaluated by the high-pressure slow constant cooling KHI test method. Some of the tested polymers showed a better KHI effect than PVCap.

Impact of Poly(dimethylsiloxane) Surface Modification with Conventional and Amino Acid-Conjugated Self-Assembled Monolayers on the Differentiation of Induced Pluripotent Stem Cells into Cardiomyocytes.

Cardiomyocytes, differentiated from induced pluripotent stem cells (iPSCs), have the potential to produce patient- and disease-specific pharmacological and toxicological platforms, in addition to their cardiac cell therapy applications. However, the lack of both a robust and a simple procedure for scalable cell substrate production is one of the major limitations in this area. Mimicking the natural healthy myocardium extracellular matrix (ECM) properties by altering the cell substrate properties, such as stiffness and chemical/biochemical composition, can significantly affect cell substrate interfacial characteristics and potentially influence cellular behavior and differentiation of iPSCs to cardiomyocytes. Here, we propose a systematic and biomimetic approach, based on the preparation of poly(dimethylsiloxane) (PDMS) substrates having the similar stiffness as healthy heart tissue and a well-defined surface chemistry obtained by conventional [(3-aminopropyl)triethoxysilane (APTES) and octadecyltrimethoxysilane (OTS)] and amino acid (histidine and leucine)-conjugated self-assembled monolayers (SAMs). Among a wide range of different concentrations, the 50:1 prepolymer cross-linker ratio of PDMS allowed adaptation of the myocardium stiffness with a Young's modulus of 23.79 ± 0.61 kPa. Compared with conventional SAM modification, amino acid-conjugated SAMs greatly improved iPSC adhesion, viability, and cardiac marker expression by increasing surface biomimetic properties, whereas all SAMs enhanced cell behavior, with respect to native PDMS. Furthermore, leucine-conjugated SAM modification provided the best environment for cardiac differentiation of iPSCs. This optimized approach can be easily adapted for cardiac differentiation of iPSCs in vitro, rendering a very promising tool for microfluidics, drug screening, and organ-on-chip platforms.

Design and preparation of poly(tannic acid) nanoparticles with intrinsic fluorescence: A sensitive detector of picric acid

Novel fluorescent poly(tannic acid) nanoparticles (FPTA NPs) were successfully synthesized via the self-polymerization reaction of tannic acid (TA) being followed by the degradation with hydrogen peroxide (H2O2). The as-prepared FPTA NPs possessed excellent intrinsic fluorescence characteristics as well as the features of low-cost, good biodegradation, convenient and large-scale preparation. It was found that picric acid (PA) could act as a strong quencher for FPTA NPs. Subsequently, the FPTA NPs-based fluorescent sensor was used for PA detection, which showed a sensitive and fast response towards PA. The utilizations of TA are mainly in the field of surface modification, and this work is the first report on utilizing the autofluorescence characteristics of FPTA NPs in sensor development, which will further broaden the application of TA. The method is of profound meanings for the excellent sensitivity and selectivity and low cost from the engineering viewpoint.

Preparation of poly(MPAEMA)/halloysite Nanocomposites and Investigation of Antiproliferative Activity

Abstract. In this present work, the synthesis, characterization, and thermal properties of poly(2-(4-methoxyphenylamino)-2-oxoethyl methacrylate) (MPAEMA) polymer/clay-based nanocomposites were investigated by in-situ polymerization. At the characterizations of nanomaterials FTIR, XRD, SEM, and TGA techniques were used. It was determined from XRD and SEM measurements that the morphology of nanocomposites was exfoliated when the clay content in the polymer matrix was kept at 3% and 5%. From thermal analysis, a positive correlation was observed between the clay ratio and thermal stability of nanomaterials. Also, the cytotoxic effect of halloysite and its nanocomposites was investigated using XTT assay on HeLa cells. According to the results, nanocomposites showed a non-cytotoxic response and thus they may use safety in many research areas such as medicine, agriculture, cosmetics.
 
 Resumen. En este trabajo, se reporta la síntesis, caracterización y propiedades térmicas de nanocompuestos de polímero / arcilla poli(2-(4-metoxifenilamino)-2-oxoetil metacrilato) (MPAEMA), obtenidos mediante polimerización in situ. Para caracterizar los nanomateriales se utilizaron las siguientes técnicas: FTIR, XRD, SEM y TGA. A partir de las mediciones de XRD y SEM se determinó que la morfología de los nanocompuestos muestra exfoliación, cuando el contenido de arcilla en la matriz de polímero se mantiene en 3% y 5%. Estudios mediante análisis térmico muestran una correlación positiva entre la relación de arcilla y la estabilidad térmica de los nanomateriales. También se investigó el efecto citotóxico de la halloysita y sus nanocompuestos utilizando el ensayo XTT en células HeLa. Los resultados muestran que los nanocompuestos tienen una respuesta no citotóxica y, por lo tanto, pueden utilizarse con seguridad en muchas áreas de investigación en disciplinas como la medicina, la agricultura y la cosmética.

Preparation of Poly(Acrylic Acid) Grafted Reduced Graphene Oxide/Polyacrylamide Composite Hydrogels with Good Electronic and Mechanical Properties by in-situ Polymerization

Conductive hydrogels with excellent electronic and mechanical properties are promising materials for flexible sensors. Herein we present a facile method to prepare reduced graphene oxide (rGO)-containing composite hydrogels with suitable electronic and mechanical properties. Poly(acrylic acid) grafted reduced graphene oxide (rGO-g-PAA) was synthesized from GO via a two-step process and then incorporated into chemically crosslinked polyacrylamide (PAM) networks by in-situ polymerization to give rGO-g-PAA/PAM composite hydrogels. The grafted PAA chains on rGO helped produce a stable and homogeneous dispersion of rGO-g-PAA in the PAM in the polymerization process. Hydrogen bonds existed between the grafted PAA chains and the PAM matrix, which not only improved the interfacial interaction between rGO and PAM matrix but also served as sacrificial bonds to dissipate energy. The rGO-g-PAA/PAM composite hydrogels exhibited enhanced tensile properties, rapid self-recovery, satisfactory electrical conductivity and remarkable resistance change upon stretching, all of which means it has the potential to be used as flexible strain sensors.

Monolithic hydrophobic cryogel columns for protein separation

The present study was conducted for the synthesis of a novel supermacroporous monolithic hydrophobic adsorbent for lysozyme (Lyz) selected as a model protein from aqueous solution. After preparation of poly(2-hydroxyethyl methacrylate-co-N-methacryloyl-(l)-tyrosine methyl ester) monolithic cryogel column, 1-naphthylamine was covalently attached, and the prepared column was abbreviated as NA-Mcc. Scanning electron microscopy, Fourier transform infrared spectroscopy and Brunauer, Emmett and Teller device were utilized for the morphology, functional groups and surface area measurements of the column. Effects of several parameters including Lyz content of the adsorption solution, pH of the medium used, ambient temperature, type of salt and flow rate on the adsorption capacity of the polymeric material were examined in continuous operation. The maximum value achieved for Lyz adsorption from aqueous phase was found to be 105.8 mg/g in phosphate buffer. In addition, NA-Mcc was investigated in terms of reusability, and it was demonstrated that there is no significant change in the adsorption properties of prepared monolithic hydrophobic cryogels after 30 adsorption–desorption cycles.

One‐step preparation of poly(NIPAM‐pyrrole) electroconductive composite hydrogel and its dielectric properties

AbstractConductive polymers and hydrogels are two of the hot prospect polymer types that are used for new stimuli responsive materials. In this study, one‐step preparation of electroconductive composite hydrogels containing polypyrrole (PPy) and N‐isopropylacrylamide (NIPAM) using free radical polymerization technique was achieved with N,N‐methylenebisacrylamide as a crosslinker and ammonium peroxy disulphate (APS) as initiator, in mixture of water/isopropyl alcohol. The equilibrium swelling degree of the poly(NIPAM)‐pyrrole) electroconductive composite hydrogel was 9.88 g of H2O/g dry polymer. According to TGA results, the thermal stability of the prepared composite poly(NIPAM‐PPy) conductive hydrogel (700°C) hydrogel is higher than that of pure poly(NIPAM) hydrogel (600°C). Furthermore, prepared samples were characterized by FTIR, and SEM analyzes. Later, the samples were pressured into pellets so that electrical impedance spectroscopy (EIS) measurements were taken between 10 and 10 MHz at room temperature. The dielectric constant value of composite poly(NIPAM‐PPy) hydrogel at 10 Hz is almost 10 times higher than that of poly(NIPAM) hydrogel. Both samples' real and imaginary parts of dielectric constant decreased with increased frequency. Samples exhibited non‐Debye relaxation since experimental data fit into dielectric model of Havriliak‐Negami. Moreover, low frequency data yielded d.c. conductivity of the pure and composite samples as 3.74 × 10−11 and 1.02 × 10−8 S/cm, respectively. Real part of impedance at low frequencies also points out ~103 times lower resistance values at 10 Hz for composite poly(NIPAM‐PPy) hydrogel. Therefore, EIS results support that electroconductive composite hydrogel fabrication was achieved using free radical polymerization technique.

Preparation of poly(ethylene-2,6-naphthalate) nanofibers by CO2 laser supersonic drawing

Poly(ethylene-2,6-naphthalate) (PEN) nanofibers were prepared by carbon dioxide laser supersonic drawing (CLSD). The CLSD method was carried out by irradiating the as-spun PEN fiber with a laser in a low-temperature supersonic jet. The supersonic jet was generated by blowing the air from the fiber supplying orifice into a vacuum chamber. The thinnest nanofiber obtained at a laser power of 4 W and a chamber pressure of −98 kPa had an average fiber diameter of 0.249 μm. The DSC curve of this nanofiber showed two melting peaks: 260 °C and 285 °C. The higher melting temperature is 25 °C higher than the melting temperature of the original fiber. The higher melting peak is caused by an increase in the intermolecular forces in the crystallite and by the tie molecules connecting adjacent crystallites becoming fully extended. Thus, nanofibers produced by CLSD exhibit a higher melting peak, which is a unique feature. The increase in melting temperature is attributed to the supramolecular sequence effect, which is a nanoscale effect. CLSD is a new method for making nanofibers without the use of any solvent or removal of a second component. Poly(ethylene-2,6-naphthalate) (PEN) nanofibers were prepared by carbon dioxide laser supersonic drawing (CLSD). The CLSD method was carried out by irradiating the as-spun PEN fiber with a laser in a low-temperature supersonic jet, which was generated by blowing the air from the fiber supplying orifice into a vacuum chamber. The DSC curve of the PEN nanofibers produced by CLSD showed two melting peaks: 260 °C and 285 °C. The increase in melting temperature is attributed to the supramolecular sequence effect, which is a nanoscale effect.

Preparation of Poly(3-hydroxybutyrate-co- 3-hydroxyvalerate) Nanofiber Catheter and Its Mechanism of Nerve Injury in Patients with Cervical Spine Injury.

At present, surgical suture treatment can be performed for spinal patients after nerve injury, but nerve regeneration and functional recovery require comprehensive treatment including drug treatment. However, there is still a lack of adjuvant therapeutic drugs that can effectively promote nerve regeneration and functional recovery. Drug treatment after nerve injury is the basis of nerve injury treatment and an important supplement to surgical treatment. Finding an effective method for treating spinal nerve injury and studying its mechanism of action may have important basic and clinical significance. The nanofiber catheter material simulates the nano/sub-micron level collagen fiber bundle structure of cells in the body, so it has been more and more widely used in the field of tissue engineering. Therefore, in this study, PHBV nanofiber catheter was successfully prepared by electrostatic spinning method, and the nanofiber catheter was characterized by SEM and DSC tests. The PHBV nanofiber catheter prepared by this research method has excellent characteristics such as porosity, large specific surface area, stable structure, thermal stability, and good mechanical properties. At the same time, adult male SD rats were selected to establish an animal model of cervical spine injury in this experiment. The expressions of three inflammation-related factors (IL-1α, IL-10 and TNF-1) were analyzed by ELISA. The results showed that in the spinal injury group, the expression of the three inflammatory factors all showed a significant increase over time and then reached a peak, then decreased and stabilized. This showed that the PHBV nanofiber catheter repairs cervical spine injury by affecting the inflammatory response, which is conducive to repairing cervical spine injury. RT-PCR was used to detect the expression of CNTF, GAP-43, and Tubulin-related proteins. During the neural regeneration process in rats, the expressions of both backbone proteins continued to be expressed, and they were first up-regulated and then flattened. This indicated that in the early stage of neural regeneration, a large number of skeletal proteins are synthesized, and they continue to be expressed at low levels over time, laying a foundation for the axon skeleton reconstruction.

Preparation of Poly[lactic-co-glycolic] Acid Nanospheres and Its Role in Hepatoma Cells.

Poly[lactic-co-glycolic] acid (PLGA) targeting nanoparticles AFP/PLGA/Dt386, loaded with Dt386 plasmid of diphtheria toxin gene, modified by Alpha fetoprotein (AFP) monoclonal antibody, is prepared. Its physical and chemical properties and its effect on HepG2 cells are studied. Firstly, Dt386 expression plasmid pET11a/Dt386 is constructed and PLGA nanoparticles are prepared by emulsion solvent evaporation (ESE). Scanning electron microscope (SEM) is used to observe its morphology. Laser Particle Sizer is used to measure the particle size. In addition, the encapsulation efficiency, drug loading and in vitro release rate of PLGA nanoparticles are measured. Carboxy fluorescein and rhodamine fluorescein are used to double label IgG/PLGA/Dt386 and AFP/PLGA/Dt386 nanospheres, respectively, the entry of nanospheres into HepG2 cells are observed at 3 h and 12 h. The effect of AFP/PLGA/Dt386 nanospheres on the migration of HepG2 cells is examined by wounding healing assay. Transwell chamber experiment is used to detect the effect of AFP/PLGA/Dt386 nanospheres on the invasion of HepG2 cells. MTT method is utilized to determine the inhibitory activity of nanoparticles on HepG2 cell proliferation. After treated with IgG/PLGA/Dt386 and AFP/PLGA/Dt386 nanoparticles for 48 hours, flow cytometry is used to detect the apoptosis rate and cell cycle of HepG2 cells in each group. The results show that the prepared nanospheres have regular morphology, flat surface, average particle size of 265.72±12.46 nm, zeta potential of -18.15 mV. The average entrapment efficiency and drug loading are 78.48±1.71% and 3.16±0.35%, respectively. The nanoparticles release slowly and stably in vitro. At the 10th day, the release rate reaches 75.13%. PLGA nanospheres can effectively protect DNA from nuclease degradation. The results show that AFP/PLGA/Dt386 nanospheres have biological targeting effect and can be enriched in cells. AFP/PLGA/Dt386 nanoparticles can significantly inhibit the migration, invasion and proliferation of HepG2 cells, and promote apoptosis.

Preparation of Self-healing Additives for Concrete via Miniemulsion Polymerization: Formulation and Production Challenges

Concrete structures undergo internal damage; this usually starts at the atomic level with defects that then grow and form cracks, which can propagate through the material. Here, a method of preparation of poly(methyl methacrylate) (PMMA) nanocapsules adhesive system via miniemulsion polymerization technique is reported, where MMA + DMA (resin + accelerator) and BPO (hardener) components are separately encapsulated by PMMA shells. The crack-healing potential of these nanocapsules was then investigated by embedding them into the mortar matrix. The prepared PMMA core–shell self-healing nanostructures survived the mixing and hardening processes, and the hardened mortar alkaline environment. The stress fields associated with propagating cracks (load‐induced cracking) broke the brittle/weak inert shell of these core–shell structures, resulted in releasing the healing agents to bridge the nascent and early-stage fractures (< 10 µm) in a short time. Long-term healing was achieved through the formation of polymorph calcite crystals in the presence of moisture and CO2, which improved the durability of mortar by filling the gaps. Formulation design (addition of chemical admixtures) and process parameters (blade design and mixing speed) were found to directly impact the uniform distribution of nanocapsules, the survival rate of nanocapsules, and the overall strength of the hardened concrete. The stepwise approach to formulate and fabricate a novel high-strength self-healing concrete system unlocks unique opportunities to design nanomaterials that safeguard the integrity of concrete structures.