Free Radical Initiator Research Articles

Tumour‐microenvironment‐responsive Na2S2O8 nanocrystals encapsulated in hollow organosilica–metal–phenolic networks for cycling persistent tumour‐dynamic therapy

AbstractTraditional tumour‐dynamic therapy still inevitably faces the critical challenge of limited reactive oxygen species (ROS)‐generating efficiency due to tumour hypoxia, extreme pH condition for Fenton reaction, and unsustainable mono‐catalytic reaction. To fight against these issues, we skilfully develop a tumour‐microenvironment‐driven yolk‐shell nanoreactor to realize the high‐efficiency persistent dynamic therapy via cascade‐responsive dual cycling amplification of •SO4−/•OH radicals. The nanoreactor with an ultrahigh payload of free radical initiator is designed by encapsulating the Na2S2O8 nanocrystals into hollow tetra‐sulphide‐introduced mesoporous silica (HTSMS) and afterward enclosed by epigallocatechin gallate (EG)‐Fe(II) cross‐linking. Within the tumour microenvironment, the intracellular glutathione (GSH) can trigger the tetra‐sulphide cleavage of nanoreactors to explosively release Na+/S2O82−/Fe2+ and EG. Then a sequence of cascade reactions will be activated to efficiently generate •SO4− (Fe2+‐catalyzed S2O82− oxidation), proton (•SO4−‐catalyzed H2O decomposition), and •OH (proton‐intensified Fenton oxidation). Synchronously, the oxidation‐generated Fe3+ will be in turn recovered into Fe2+ by excessive EG to circularly amplify •SO4−/•OH radicals. The nanoreactors can also disrupt the intracellular osmolarity homeostasis by Na+ overload and weaken the ROS‐scavenging systems by GSH exhaustion to further amplify oxidative stress. Our yolk–shell nanoreactors can efficiently eradicate tumours via multiple oxidative stress amplification, which will provide a perspective to explore dynamic therapy.

A Novel Banana Fiber Reinforced Green Composite from Maleated Castor Oil and Linseed Oil

In recent decades, the consumerist society has recognized the consequences of petrochemicals, hence the interest of scientists has been drawn toward renewable products obtained from biological sources. In this study a novel biocomposite with the use of the least chemicals was fabricated by crosslinking maleated castor oil (MACO) and linseed oil (LO) by free radical polymerization, using benzoyl peroxide (BPO) as the free radical initiator. The significance of this study is that the polymer matrix is derived entirely from vegetable oils with slight modifications. Banana fibers are one of the strongest natural fibers that may be taken from the banana pseudo-stem that is discarded after the fruit is harvested. To convert this post-harvest waste into a value-added product, NaOH-treated banana fibers were used as the reinforcement for the developed composite. The characterization of the fibers and the composites was carried out by performing Fourier-transform infrared spectroscopy (FT-IR), X-Ray diffraction analysis (XRD), Dynamic mechanical analysis, tensile and compressive stress analysis, Scanning electron microscopy (SEM), Thermogravimetric (TG)/derivative thermogravimetric (DTG) and thermal conductivity analysis. Composites were also analyzed for their water absorptivity and chemical resistivity. The influence of varying banana fiber weights on the composite’s mechanical strength was investigated using a dual cantilever flexural test. It revealed that the composite’s strength increased with increasing fiber content until 50% (w/w) and then dropped as the fiber content increased further. The maximum tensile strength of the optimum composite was 16.92 ± 4.70 Megapascal (MPa) and the composite was resistant against a compressive force of 4,500 kN without any fractures. The composites’ water absorptivity and chemical resistivity tests revealed that increasing the fiber content enhanced the composites'swelling. The composite was acidic and saline water resistant, but not alkaline solution resistant. Additionally, the thermal conductivity measurements of the composite showed that the composite is a thermal insulator. The composite with 50% (w/w) fiber load, 20% (w/w) BPO, 10% (w/w), LO and 20% (w/w) MACO exhibited the best overall performances.

Comprehensive Biodegradation Analysis of Chemically Modified Poly(3-hydroxybutyrate) Materials with Different Crystal Structures.

This work presents a comprehensive analysis of the biodegradation of polyhydroxybutyrate (PHB) and chemically modified PHB with different chemical and crystal structures in a soil environment. A polymer modification reaction was performed during preparation of the chemically modified PHB films, utilizing 2,5-dimethyl-2,5-di(tert-butylperoxy)-hexane as a free-radical initiator and maleic anhydride. Films of neat PHB and chemically modified PHB were prepared by extrusion and thermocompression. The biological agent employed was natural mixed microflora in the form of garden soil. The course and extent of biodegradation of the films was investigated by applying various techniques, as follows: a respirometry test to determine the production of carbon dioxide through microbial degradation; scanning electron microscopy (SEM); optical microscopy; fluorescence microscopy; differential scanning calorimetry (DSC); and X-ray diffraction (XRD). Next-generation sequencing was carried out to study the microbial community involved in biodegradation of the films. Findings from the respirometry test indicated that biodegradation of the extruded and chemically modified PHB followed a multistage (2-3) course, which varied according to the spatial distribution of amorphous and crystalline regions and their spherulitic morphology. SEM and polarized optical microscopy (POM) confirmed that the rate of biodegradation depended on the availability of the amorphous phase in the interspherulitic region and the width of the interlamellar region in the first stage, while dependence on the size of spherulites and thickness of spherulitic lamellae was evident in the second stage. X-ray diffraction revealed that orthorhombic α-form crystals with helical chain conformation degraded concurrently with β-form crystals with planar zigzag conformation. The nucleation of PHB crystals after 90 days of biodegradation was identified by DSC and POM, a phenomenon which impeded biodegradation. Fluorescence microscopy evidenced that the crystal structure of PHB affected the physiological behavior of soil microorganisms in contact with the surfaces of the films.

Tannin-Assisted Synthesis of Nanocomposites Loaded with Silver Nanoparticles and Their Multifunctional Applications.

Nanocomposites have been widely used in many important areas due to their particular physical/chemical properties; however, just though a simple technology, endowing multiple functions into a single nanomaterial for realizing their multifunctional applications is still a challenge. Here, we report a robust method for the facile synthesis of Ag-based multifunctional nanocomposites via using tannin-coated phenol-formaldehyde resin nanospheres (TA-PFRN) as silver nanoparticle (Ag NP) carriers. The thickness of the tannin coating is readily tuned from 50 to 320 nm by regulating the concentration of tannin added. Under the optimal conditions, the TA-PFRN has a 23.8 wt % of Ag NPs loading capacity with only 17.2 nm Ag NP layers. Consequently, the novel TA-PFRN@Ag nanocomposites possess multiple functions and integrated characteristics. As catalysts, the catalytic efficiency of TA-PFRN@Ag is nearly 6 times higher than that of the PFRN@Ag. As highly effective free radical initiators, TA-PFRN@Ag nanocomposites can trigger ultrafast acrylic acid (AA)/acrylamide (AM) polymerization at room temperature (in only a few minutes). As nano-reinforced fillers, the addition of 0.04 wt % nanocomposites can improve the tensile strength of PVA film from 60 to 153.2 MPa. In addition, the nanocomposites can also serve as antibacterial agents, efficiently inhibiting the growth of Escherichia coli (E.coli) and Staphylococcus aureus (S.aureus); as antiultraviolet agents, the presence of TA-PFRN@Ag nanocomposites endows the film/hydrogel materials excellent ultraviolet (UV) shielding. This work provides a novel strategy for the green synthesis of Ag-based multifunctional nanocomposites that show promising applications in catalysis, nanomaterials, and biomedicine.

Designing of molecularly imprinted polymer with carboxylic acid functionality for chiral separation of (±)‐3,4‐methylenedioxymethamphetamine

AbstractIn this work, we discuss the development of a long‐lasting enantioselective material for the effective enantio‐recognition of S‐3,4‐methylenedioxymethamphetamine (S‐MDMA) and chiral separation of the (±)‐MDMA racemate using a crosslinked poly(acrylic acid‐4‐vinylpyridine) copolymer. The first step was the synthesis and characterization of an acryloyl‐S‐MDMA amide. After that, the free radical initiator azobisisobutyronitrile was used to copolymerize the synthesized chiral amide with 4‐vinylpyridine and divinylbenzene. The incorporated S‐MDMA species were extracted from the polymeric particles by heating them with sodium hydroxide, followed by rinsing with hydrochloric acid. This developed the molecularly imprinted S‐MDMA particles, which were visualized with a scanning electron microscope and Fourier transform infrared spectroscopy. The selectivity parameters indicated a higher affinity of the fabricated S‐MDMA imprinted particles toward S‐MDMA, around 10‐fold higher than that related to R‐MDMA. Results from Langmuir adsorption experiments at pH 6 demonstrated a maximal capacity of 142 mg g−1. In addition, the values of enantiomeric excess were found to be 94.5% and 79.4% for R‐ and S‐MDMA in the loading and eluant solutions, respectively, after optical separation was done using the column technique. © 2023 Society of Industrial Chemistry.

Three-Component Tandem Amidosulfenylation of Alkenes for the Synthesis of β-Succinimide Sulfides.

An environmentally benign multicomponent strategy for the amidosulfenylation of alkenes for the synthesis of β-succinimide sulfides is disclosed. In this process, common disulfides smoothly act as a sulfur-based source, and N-iodosuccinimide (NIS) is used not only as a free radical initiator but also as an N-nucleophile. A broad range of functional groups are tolerated in this reaction system.

The effects of cellulose nanocrystal and dicumyl peroxide on the crystallization kinetics of polylactic acid

AbstractCellulose nanocrystals (CNCs) have been blended into polylactic acid (PLA) to improve the polymer's properties. The dispersion of CNC in the matrix has a strong influence on the properties of the nanocomposites. In this study, PLA and CNC were compounded by a reactive extrusion process using dicarbonyl peroxide (DCP) as the free radical initiator. Isothermal and non‐isothermal crystallization kinetics of the resulting nanocomposites were investigated to understand the effect of PLA‐D‐CNC on the crystallization of the materials. Nuclear magnetic resonance and Fourier transform infrared spectroscopy analyses confirmed the grafting of PLA onto CNC via reactive extrusion. The Avrami and Tobin model studies showed that the reactive extrusion product PLA‐D‐CNC exhibited much higher crystallization rates compared to neat PLA, PLA/CNC (without DCP), and PLA/DCP. The maximum crystallization rate temperature of PLA, PLA/CNC, and PLA/DCP was increased from ~100 to ~110°C for PLA‐D‐CNC. The results showed that CNC promoted PLA nucleation and crystallization at high temperatures under the action of DCP. Specifically, the maximum crystallization rate of PLA‐D‐CNC was 46 times higher than that of neat PLA. PLA‐D‐CNC showed a two‐stage crystallization process, while the other three samples exhibited mostly single‐stage processes. The much‐enhanced crystallization of PLA‐D‐CNC was ascribed to the improved interaction between PLA and PLA‐D‐CNC and the homogeneous dispersion of CNC.Highlights PLA chains were grafted onto CNC with the assistance of DCP free radicals. PLA‐grafted CNC facilitated heterogeneous nucleation of PLA. Crystallization studies confirmed improved PLA crystallization in the presence of PLA‐D‐CNC.

Mechanism of iron salt impregnated biowaste biochar with a prevailing free radical initiator for effective removal of toxic thallium from solution

Thallium is an emerging metallic pollutant with extremely high toxicity which resulted in worldwide water pollution in the past decades. It is critical to develop multiple alternative methods for Tl removal to enrich control strategy towards Tl pollution in aquatic environment. It is proposed herein a highly effective and environmental-friendly Tl removal method by applying iron salt-impregnated biochar (BC) combined with persulfate (PS), using two most common iron salts (FeCl3 and Fe(NO3)3). It was found that FeCl3@BC-PS system achieved higher Tl removal capacity (164.42 mg/g), which exhibited a comparative preponderance relative to the reported iron based adsorbent composites, partially owing to significantly enhanced specific surface area (854.48 m2/g). The dominant Tl removal mechanisms include free radical based oxidation and chemical adsorption. Radical quenching experiments confirmed that SO4− and OH served as vital radicals for FeCl3@BC-PS and Fe(NO3)3@BC-PS, respectively. The study provides a reliable alternative for Tl-wastewater treatment with PS activation by catalyst based on the synergistic effect of biochar and iron salts.

On-Demand Free Radical Release by Laser Irradiation for Photothermal-Thermodynamic Biofilm Inactivation and Tooth Whitening.

Dental diseases associated with biofilm infections and tooth staining affect billions of people worldwide. In this study, we combine photothermal agents (MoS2@BSA nanosheets, MB NSs), a thermolysis free-radical initiator (AIPH), and carbomer gel to develop laser-responsive hydrogel (MBA-CB Gel) for biofilm inactivating and tooth whitening. Under a physiological temperature without laser irradiation, MB NSs can eliminate free radicals generated from the slow decomposition of AIPH due to their antioxidative activity, thereby avoiding potential side effects. A cytotoxicity study indicates that MB NSs can protect mammalian cells from the free radicals released from AIPH without laser irradiation. Upon exposure to laser irradiation, MB NSs promote the rapid decomposition of AIPH to release free radicals by photothermal effect, suggesting their on-demand release ability of free radicals. In vitro experimental results show that the bacteria inactivation efficiency is 99.91% (3.01 log units) for planktonic Streptococcus mutans (S. mutans) and 99.98% (3.83 log units) for planktonic methicillin-resistant Staphylococcus aureus (MRSA) by the mixed solution of MB NSs and AIPH (MBA solution) under 808 nm laser irradiation (1.0 W/cm2, 5 min). For S. mutans biofilms, an MBA solution can inactivate 99.97% (3.63 log units) of the bacteria under similar laser irradiation conditions. Moreover, MBA-CB Gel can whiten an indigo carmine-stained tooth under laser irradiation after 60 min of laser treatment, and the color difference (ΔE) in the teeth of the MBA-CB Gel treatment group was 10.9 times that of the control group. This study demonstrates the potential of MBA-CB Gel as a promising platform for biofilm inactivation and tooth whitening. It is worth noting that, since this study only used stained models of extracted teeth, the research results may not fully reflect the actual clinic situation. Future clinical research needs to further validate these findings.

Cellulose nanocrystal/polymer nanocomposite latex via surfactant-free emulsion polymerization

Polar cellulose nanocrystals (CNCs) are difficult to disperse well in hydrophobic polymer matrices, and usually surfactants or expensive and time-consuming functionalization of the reinforcement or matrix have been attempted to improve dispersion. Here, we report a new, facile method to prepare CNC/polymer nanocomposite latices directly via surfactant-free emulsion polymerization of vinyl monomers and CNCs initiated by a cationic, water-soluble, free-radical initiator. The distribution of CNCs in the latex particles can be tailored through controlling the reaction procedures, namely, whether the monomers are added before or after preheating the CNCs with the initiator and has been confirmed by scanning electron microscopy (SEM) and scanning transmission X-ray microscopy (STXM) studies. CNCs distribute inside the latex particles if the monomers are added after the preheating step, and owing to the more even distribution of CNCs, such nanocomposite latices exhibit better mechanical properties than those prepared without preheating or via physically mixing CNCs with emulsions polymerized using conventional surfactant system. A latex particle formation mechanism is proposed based on these phenomena and polymerization kinetics studied in this work. Unlike typical CNC-based Pickering emulsion polymerization, our process can be operated without the need for intense mechanical shearing and provide an industrially scalable approach to prepare stable CNC/polymer nanocomposite latices that can be melt processed or used directly in a variety of applications, such as paints and coatings, adhesives, or cosmetics.

CARD11: Polymeric Endoluminal Paving for Prevention of Paravalvular Leak in Transcatheter Aortic Valve Replacement

Background: Calcific aortic valve disease and associated aortic stenosis is increasingly common, with prevalence across the age spectrum. Transcatheter aortic valve replacement (TAVR) has emerged as a life-saving, non-surgical alternative for replacement of diseased aortic valves, restoring non-obstructive blood flow from the heart. While effective, current TAVR technology remains limited by adaptability to patient-specific anatomy, leading to incomplete deployment and non-conformal fit resulting in paravalvular leak. Polymeric endoluminal paving was previously developed as a methodology allowing deployment of polymeric materials on tissue surfaces, serving as structural materials and barriers. Here we adapt the paving methodology to fill gaps and defects resulting from incomplete TAVR valve deployment to limit paravalvular leak. Specifically, we assess the efficacy pf polymeric paving in vitro as a means of gap filling and leak reduction in valves deployed in 3-D physical models of severely stenosed aortic valves. We hypothesize that applied polymeric biomaterials will fill and conform to irregular aortic valve geometries acting as a sealant to reduce paravalvular leak. Methods: Polymeric hydrogels were prepared from ABA block copolymer macromers composed of diacrylate terminated by PLA-b-PEG-b-PLA. Hydrogel networks were prepared by swelling these macromers, following the addition of free radical initiators. Hollow tubular constructs were formed via melt-processing in PDMS molds to fit as a “sleeve” around deployed PolyV® nitinol stent (Fig 1A). The sealing efficacy of polymers was examined using a silicone replica of CAVD aortic root with deployed stent + polymer construct (Fig 1B). A rubber stopper was used to fully occlude aortic lumen and restrict flow to paravalvular areas for quantitative analysis. To test sealing against hydrostatic pressure, valve construct was connected to Tygon tubing and water was added at equivalent 10 mmHg increments at 5-minute intervals. Volume from paravalvular flow was measured at each step. Experiments were performed with N = 4 polymeric sleeves. Results: We found significant reduction in paravalvular leakage with polymer sleeves compared to no polymer at all pressures tested. Figure 1C shows the mean ± standard deviation volume of water leaked over 5 minutes of corresponding hydrostatic pressure. No leakage was detected up to 60mmHg for all polymer sleeves tested. At approximately 85-90 mmHg, the rubber stopper failed, however the polymer sleeve remained intact. Conclusions: Polymeric paving utilized with TAVR is a promising combinative therapy for preventing paravalvular leakage. Our results indicate that potential polymeric biomaterials are capable of conforming to non-physiologic aortic valve morphologies, filling and sealing paravalvular gaps, while withstanding physiologic trans-aortic pressures. With further translation, polymer paving can be useful in improving TAVR outcomes.

Interactions of Free Radical Initiators and Antioxidants in Erythrocytes: An Ex Vivo Study

Interactions of Free Radical Initiators and Antioxidants in Erythrocytes: An Ex Vivo Study

Film-blown blends of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by compatibilization with poly(butylene-co-succinate-co-adipate) with a free radical initiator

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a sustainable and biodegradable polymer that has potential for use in food packaging. However, its low melt strength makes it difficult to process using film-blowing techniques. To address this issue, 70% PHBV and 30% poly(butylene-co-succinate-co-adipate) (PBSA) were blended with dicumyl peroxide (DCP) as a compatibilizer. The resulting blend showed crosslinking and the presence of long-branched structures, as evidenced by Cole-Cole and van-Gurp-Palmen plots. The optimum formulation (30% PBSA and 0.1 phr DCP) improved the melt flow index, reducing it from 90 g/10 min (neat PHBV) to 22 g/10 min. This allowed for the successful small-scale production of blown PHBV/PBSA films. The thermal properties of PHBV, such as the glass transition and crystallinity index, remained unchanged with the addition of DCP. The films displayed a brittle behavior and a lower modulus compared to neat PHBV. However, they could be heat-sealed, and their mechanical properties remained stable during a six-month storage experiment under freezer conditions. Overall, the compatibilized PHBV/PBSA blend shows potential for use in the production of packaging films through film blowing.

Fabrication and Evaluation of Aceclofenac-loaded Sustained-Release Mucoadhesive Tablet Composed of Cassia fistula Seed Gum-Grafted-Poly (Sodium Acrylate)

Aim: This study was aimed to fabricate gastroretentive mucoadhesive sustained-release tablets of aceclofenac with Cassia fistula seed gum-grafted-poly(sodium acrylate) and evaluate them.
 Background: Aceclofenac has several gastric related side effects such as increase in acid secretion, gastritis, burning sensation, nausea, vomiting, etc. Sustained-release tablet may reduce these because of slow drug release. But long term use of conventional sustained-release tablets of NSAIDs showed to develop colorectal ulcer. Gastroretentive sustained-release devices may eliminate this problem.
 Objective: The objective was to synthesis Cassia fistula seed gum-grafted-poly(sodium acrylate) and apply it in the fabrication of novel mucoadhesive sustained-release tablet for aceclofenac delivery in stomach.
 Method: CFSG-grafted-poly(sodium acrylate) (CFSG-g-PSA) was synthesized by microwave-assisted free-radical initiation method using ceric ammonium nitrate (CAN) as free-radical initiator. The tablets were prepared with the graft-copolymer by wet granulation technique. Compatibility between drug and graft-copolymer was checked by FTIR, DSC and PXRD. Surface topography of the uncoated matrix tablets was studied by SEM. The tablets were evaluated for weight variation, content uniformity, dimension, disintegration test, mucoadhesive and drug-release. accelerated stability study was also done.
 Results: FTIR, DSC and PXRD studies substantiated the drug-polymer compatibility. The evaluation parameters were within prescribed limit. The study revealed excellent mucoadhesive property over 10 h and sustained-drug-release pattern following zero order kinetic. Similarity factor was found to be 83.4.
 Conclusion: The study demonstrates a simple approach of functionalization of biopolymer towards development of gastroretentive mucoadhesive sustained-release tablet formulation.

A comparative study on graft copolymerization of MMA onto wood fiber under microwave and conventional heating

Wood polymer composites (WPC) are gaining popularity and widespread usage due to an increased awareness of human population towards the importance of environmental effects and green eco-friendly materials. Mechanical properties of WPC could be improved through graft copolymerization of monomer onto wood fiber to improve interfacial bonding. In this study, a comparison of free radical graft copolymerization using microwave-assisted and conventional heating method was performed. Methyl methacrylate (MMA) monomer is used in graft copolymerization of Meranti wood using a free radical initiator system consisting of ferrous sulfate and hydrogen peroxide. Grafting reaction time was varied while other graft parameters were kept constant including monomer concentration, initiator molar ratio, reaction temperature and solvent volume. Maximum graft yield of 11.75% and 10.17% were obtained for water bath heated and microwave-assisted method respectively. The presence of grafted monomer was proven by FTIR spectra analysis. Thermogravimetric analysis performed on grafted wood fibers showed improved thermal resistance compared to ungrafted wood fiber.

Synthesis, Characterisation and Comparative Study of Hydrogel and Nanogels of Psyllium

Natural polysaccharides are being explored as the matrices for attaining speciality materials for pharmaceutical, medicinal and environmental applications via chemical modification such as grafting. Psyllium polysaccharide-based hydrogels and nanogels have potential biomedical and water purification applications due to their advantageous properties such as stimulus responsiveness, biocompatibility, target drug delivery and stability. The present study aims to synthesise hydrogel and nanogels of psyllium and attain comparative data for the two to undermine their potential applications. Psyllium– cl –N,N–MBAm–poly(AAm) hydrogel (Psy-MBAm-AAm – hg) and Psyllium– cl –N,N–MBAm–poly(AAm) nanogel (Psy-MBAm-AAm – ng) were synthesised by grafting acrylamide (AAm) onto psyllium using ammonium persulphate (APS) as a free radical initiator in a redox system where N, N-methylene bisacrylamide acted as a crosslinker. The comparative study of synthesised gels was carried out by studying swelling characteristics at acidic and basic pH (7 and 4) and at varied temperatures for both matrices. The synthesised hydrogel and nanogels were subjected to characterisation by Fourier transform infrared spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), and Zeta Potential Analysis to get evidence for successful synthesis and nanogel formation.

Multicolor, injectable BSA-based lanthanide luminescent hydrogels with biodegradability

Protein hydrogels have attracted increasing attention because of their excellent biodegradability and biocompatibility, but frequently suffer from the single structures and functions. As a combination of luminescent materials and biomaterials, multifunctional protein luminescent hydrogels can exhibit wider applications in various fields. Herein, we report a novel, multicolor tunable, injectable, and biodegradable protein-based lanthanide luminescent hydrogel. In this work, urea was utilized to denature BSA to expose disulfide bonds, and tris(2-carboxyethyl)phosphine (TCEP) was employed to break the disulfide bonds in BSA to generate free thiols. A part of free thiols in BSA rearranged into disulfide bonds to form a crosslinked network. In addition, lanthanide complexes (Ln(4-VDPA)3), containing multiple active reaction sites, could react with the remaining thiols in BSA to form the second crosslinked network. The whole process avoids the use of nonenvironmentally friendly photoinitiators and free radical initiators. The rheological properties and structure of hydrogels were investigated, and the luminescent performances of hydrogels were studied in detail. Finally, the injectability and biodegradability of hydrogels were verified. This work will provide a feasible strategy for the design and fabrication of multifunctional protein luminescent hydrogels, which may have further applications in biomedicine, optoelectronics, and information technology.

RADICAL COPOLYMERIZATION AND DETERMINATION OF THERMAL STABILITY OF SOME NEW SUBSTITUTED PHENYL MALEIMIDE POLYMERS

This article investigated a study and application of Kuhan-mark Howink Sakwada equation on some maleimides polymerand find out a relation in between intrinsic viscosity and molecular weight. Proposed work taken some maleimidesubstituted compounds and their study. In the research we selected some new maleimides monomer like as N-(ONitrophenyl)maleimide, N-(M-Nitro phenyl) maleimide and N-(P-Nitro phenyl) maleimide. Monomers werecopolymerized with methyl methacrylate. Synthesized homo and copolymers were characterized by FT-IR and 1H-NMRspectroscopy. Prepared monomers were polymerized at 12, 36, 48 and 72 hours on magnetic stirrer and AIBN and BPOused as a free radical initiator. THF and DMF were used as a solvent. Percentage yield were determined with timevariations. Number average and weight average molecular weight was determined by the gel permissionchromatography. Intrinsic viscosity was determined by the Hubelhod viscometer and thermal stability was determined bythe TGA techniques and starting degradation temperature and final degradation temperature was recorded.Polymerization reaction proceed via free radical is determined by the PDI index. Percentage composition of N and C iscalculated in monomer and polymer. This article focused that what actual shape of the homopolymer and copolymershowing in solvent and determined by Kuhan-mark Howink Sakwada equation.

Bioorthogonal "Click Chemistry" Bone Cement with Bioinspired Natural Mimicking Microstructures for Bone Repair.

Current bone cement systems often demand free radical or metal-related initiators and/or catalysts for the crosslinking process, which may cause serious toxicity to the human body. In addition, the resultant dense scaffolds may have a prolonged degradation time and are difficult for cells to infiltrate and form new tissue. In this study, we developed a porous "click" organic-inorganic nanohybrid (PO-click-ON) cement that crosslinks via metal-free biorthogonal click chemistry and forms porous structures mimicking the native bone tissue via particulate leaching. Strain-promoted click reaction enables fast and efficient crosslinking of polymer chains with the exclusion of any toxic initiator or catalyst. The resulting PO-click-ON implants supported exceptional in vitro stem cell adhesion and osteogenic differentiation with a large portion of stem cells infiltrated deep into the scaffolds. In vivo study using a rat cranial defect model demonstrated that the PO-click-ON system achieved outstanding cell adsorption, neovascularization, and bone formation. The porous click cement developed in this study serves as a promising platform with multifunctionality for bone and other tissue engineering applications.

Thermal decomposition kinetics and mechanism investigation of cumene hydroperoxide under inert gas: A novel experimental method

Organic peroxides, due to temperature manipulation failure and/or manner disturbances, had been probable to lead to the prevalence of runaway phenomena, even fire, and explosion. Cumene hydroperoxide (CHP), is a traditional liquid organic peroxide for industrial purposes and is applied as a free radical initiator for polymerization reactions in the petrochemical industry. Its utilization in the industrial processes had certain potential safety hazards. In this work, linearly ramped thermal decomposition in CHP was performed using differential scanning calorimetry under a nitrogen atmosphere. Kinetic analysis is made using data from the ramped measurements with two integral strategies (Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose). The gaseous products of thermal decomposition in CHP are investigated via thermal gravimetric evaluation coupled with Fourier transform infrared spectroscopy and gas chromatography/mass spectrometry. Combined with the experimental results, the possible decomposition path of CHP is discussed. This makes up the gap of unclear decomposition mechanism of CHP in inert atmosphere, and has important reference significance for its industrial production and application.