LAMINATION OF POLYMER FILMS BY BULK SURFACE PHOTOGRAFTING PROCESS AND PROPERTIES

A new process for lamination of polymer films by 'bulk surface photografting' has been developed. The chemical component of the invention is that the curing of reactive solution between two substrates is initiated by the surface free radicals produced by aromatic ketones and surface-hydrogen of substrates. Using the new approach, two or more polymer films are bonded together by a grafted polymer network which is grafted to adjacent substrate surfaces. The technique has been applied to film substrates of different polymers such as polyolefins, polyesters, and polyamides which have abstractable hydrogens at the surface. The photolaminated film composites containing carrier films and an intermediate functional film of low permeability give strong laminates with high barrier properties, e.g, for oxygen and air.

MAGNETIC FIELD EFFECT ON PHOTOPOLYMERIZATION OF STYRENE MICROEMULSION

External magnetic field increases the photo-induced polymerization rate of styrene microemulsion.The type of photoinitiator plays an important role. The photoinitiators, used are dimethoxyphenyl acetophenone(DMPA), 1-hydroxycyclohexyl phenylketone (Irgacure 184) and dimethylhydroxyacetophenone (Darocur 1173). No magnetic effect was observed by using dibenzylketone (DBK) as photoinitiator. The molecular weight of the polymer is slightly affected by magnetic field. The influence of temperature has also been investigated.

CLAY CATALYZED SYNTHESIS OF BIO-DEGRADABLE POLY(GLYCOLIC ACID)

Glycolic acid was polymerized under vacuum in the presence and absence of nano sized clay.The added clay catalyzed the condensation polymerization which can be confirmed by recording FTIR spectroscopy and intrinsic viscosity (Ⅳ)values.The relative intensity of C=O/CH is increased while increasing the amount of clay.DSC showed the appearance of multiple endotherms of poly(glycolic acid).TGA showed the percentage weight residue remain above 750℃for polymer-nano composite system was 21% and hence proved the fl...

Mechanical Properties, Microstructure and Surface Quality of Polypropylene Green Composites as a Function of Sunflower Husk Waste Filler Particle Size and Content

Agricultural waste is a still untapped source of materials that can,in case of proper utilization,significantly improve the sustainability of polymers and their composites.In this work,polymer composites based on isotactic polypropylene were produced incorporating ground sunflower husk in the amount of 10 wt%and 20 wt%.The work’s main objective is to evaluate how preliminary fractioning of this agricultural waste filler affects the thermomechanical properties,microstructure and surface topology of polypropylene-based injection molded composites.The composites were analyzed for mechanical properties(tensile,impact strength and hardness),thermomechanical properties(Vicat softening point VST,heat deflection temperature HDT,and dynamic thermomechanical analysis DMTA)with reference to morphological changes evaluated using scanning electron microscopy(SEM).The quality of the produced composites was assessed on the basis of the analysis of the surface topology of the injected composites.It has been shown that the larger particle size of used filler has a direct impact on increasing composite stiffness in the room and elevated temperature.Moreover,a relationship was demonstrated between the size of the filler and the deterioration of the tensile strength in the case of composites with a higher content of filler.The results show that the addition of sunflower husk as a particle-shaped waste filler is an effective method to increase sustainability of polypropylene-based green composites with beneficial thermomechanical properties and to reduce the residue of sunflower husk from industrial oil production.

Physicochemical Properties of Gum Arabic

Gum Arabic is harvested commercially from wild trees throughout the Sahel from Senegal and Sudan to Somalia and in the northern part of Nigeria.Clumps of gum Arabic were collected and dirt particles were removed,the samples were dried and grounded to fine powder.The Physicochemical properties of gum Arabic was determined using standard methods and the values obtained showed;Moisture content 6.9%±5,Soluble content 90.6%,Viscosity 5.45±3Ns/m2,Ash content 3.2±4%,Zinc 3mg/kg,Iron 41mg/kg±5,Manganese 48.2mg/kg±5 and Copper 33.3mg/kg±2.The gum also contains carbohydrate 0.3ppm±2,protein 0.75ppm±2,starch 0.0076±10 and nitrogen 0.12ppm±5.It was observed that the gum does not contain cadmium and nickel.

Poly(phenylene oxide) and Renewable Polyamide 11 Blends Compatibilized by Ethylene-n-Octene Copolymer

Poly(phenylene oxide)/renewable polyamide 11 (PPO/PA11 20/80) blends toughened with glycidylmethacrylate grafted ethylene-n-octene copolymer (GEOC) were prepared in a co-rotating twin-screwextruder. The reaction between GEOC and PPO/PA11 blend was analyzed by gel content tests. Themorphology of PPO/PA11/GEOC blends was observed by scanning electron microscope. The SEMresults showed that PPO formed the continuous phase, though it is a minority component of blends. Withincreasing GEOC content from 5 to 15 wt% the morphology of the blends transformed from droplet-matrix toco-continuous structure, in which both PA11 and PPO phases are continuous. The blend with co-continuousmorphology had better mechanical properties than those with droplet-matrix morphology. The impactstrength of the PPO/PA11/GEOC blends was much higher compared to the one without GEOC as well asPA11 due to the compatibilizing effect, which was also proved by DSC analysis, rheological behavior (MFR,DMTA) and tensile properties.

A Study of Quality Improvement of Natural Rubber Products by Drying Methods

This experimental study was carried out to verify the quality enhancement of Natural Rubber Products by drying methods and ascertain to what extent the different methods of drying affected the properties exhibited. During this study, samples of natural rubber coagulum were obtained and a sample each was subjected to one of these three methods of drying: air, smoke and oven. The qualities of the dried rubber samples from the three methods of drying were then investigated. The criterion adopted for quality in this study was Plasticity Retention Index (PRI), which gave insight of the oxidative resistance of natural rubber, a measure of quality. The plasticity retention index was tested by using the Wallace plastimeter. The PRI values were calculated for the samples. Results obtained from this study showed that the qualities of natural rubber samples were actually influenced to different measurable extents depending on drying methods, as exhibited in the PRI levels. The results further gave basis for our conclusions that the smoke dried rubber samples had the poorest qualities, having the lowest values of PRI;followed by the oven and air dried samples respectively in terms of their PRI presented the best qualities, the highest PRI values.

Synthesis, Structural and Dielectric Properties of Ferroelectric Dichloridoglycine Zinc Dihydrate Single Crystals

The strong electro mechanical coupling exhibited by the ferroelectric materials is the remarkable feature of these materials. Therefore, they find applications in sensors, actuators for producing ultrasonics and micro positioning. The material dichloridoglycine zinc dihydrate is a centrosymmetric ferroelectric crystal. In the present study, this crystal has been grown from a mixture of glycine and zinc chloride. The dielectric constant and the dielectric loss of the grown crystal were studied as a function of frequency and temperature, and the corresponding relaxation time (τ), relaxation frequency (Fr) and the activation energy have been calculated. The ferroelectric property of the crystal has been confirmed by dielectric studies. The ferroelectric characteristics of the crystal have been studied and reported.

Study of Mechanical and Micro-Structural Effect on Alkaline Treated Sponge Gourd ( Luffa aegyptiaca ) Fibre Epoxy Composite

In this present work, the study of mechanical and micro-structural effect on alkaline treated sponge gourd fibre epoxy composite has been investigated experimentally. Composite laminates are fabricated by hand lay-up technique. Scanning Electro Microscope analysis on the composite materials is performed. A group of neat epoxy samples is fabricated for comparison purpose. Samples are analysed for their mechanical properties to establish an alkaline effect on sponge gourd. Indeed, a maximum value of strength and strain is observed over 20% filler loading for 24 hrs treated fibre composite.

Synthesis and Characterization of Nano Ag End Capped L-Cysteine Bridged Diblock Copolymer

The target of the present investigation is synthesis and characterization of an amphiphilic diblock copolymer with antibacterial property. Ring opening polymerization （ROP） of ε-caprolactone （CL） and tetrahydrofuran （THF） was carried out under inert atmosphere by using L-cysteine as a bridging agent in the presence of stannous octoate （SO） as a catalyst. The nano silver end capped diblock copolymer was synthesized by in situ method. Thus obtained nano silver end capped L-cysteine bridged diblock copolymer was characterized by various analytical methods like Fourier transform infrared （FTIR） spectroscopy, nuclear magnetic resonance （NMR） spectroscopy, circular dichroism （CD）, fluorescence spectroscopy, gel permeation chromatography （GPC）, X-ray photoelectron spectroscopy （XPS）, thermogravimetric analysis （TGA）, differential scanning calorimetry （DSC）, field emission scanning electron microscopy （FESEM）, high resolution transmission electron microscopy （HRTEM） and zeta potential. The antimicrobial property of the nano silver end capped diblock copolymer against e-coli was tested.

Thermal Degradation Kinetics of Structurally Diverse Poly(bispropargyl ethers-bismaleimide) Blends

Structurally diverse bispropargyl ethers using resorcinol,quinol,4,4￠-dihydroxy biphenyl,bisphenol-A,4,4￠-dihydroxy diphenyl ketone,4,4￠-dihydroxy diphenylsulphone,trimethyl indane bisphenol and tetramethyl spirobiindane bisphenol were prepared by using phase transfer catalyst.Synthesized materials were separately blended with 4,4￠-bismaleimido diphenyl methane（BMIM）in mole ratios（0.5：0.5）.The materials were thermally cured and the structural characterisation and the thermal properties of these cross-linked materials are investigated using Fourier-transform infrared（FTIR）spectrophotometer and thermogravimetric analyzer（TGA）.Among the different materials investigated poly MRPE,poly MBPEBPA and poly MSPE show higher onset degradation temperature of 300°C indicating higher thermal stability.The degradation kinetics is investigated using Flynn-Wall-Ozawa（FWO）,Vyazovkin（VYZ）and Friedman（FRD）methods.Amongst the various cured materials investigated,the activation energy（Ea-D）values obtained for poly MRPE and poly MKPE were observed to increase continuously froma=0.2 to 0.8 and the values range from 199 kJ/mol to 245 k J/mol and 153 k J/mol to 295 k J/mol respectively.The crosslinked materials resulting from these bispropargyl monomers definitely need more energy for bond cleavage due to the presence of more aromatic units.The volatile products obtained during the thermal degradation of the polymers were analyzed using thermogravimetric-Fourier transform infrared analyses（TG-FTIR）.The phenols,substituted phenols,carbon monoxide,carbon dioxide and small amount of aniline were found to be the major products during thermal degradation of these cured blends.

Poly[β-(1→4)-2-amino-2-deoxy-D-glucopyranose] based zero valent nickel nanocomposite for efficient reduction of nitrate in water

Chemical reduction of nitrate using metal nanoparticles has received increasing interest due to over-dependence on groundwater and consequence health hazard of the nitrate ion. One major drawback of this technique is the agglomeration of nanoparticles leading to the formation of large floes. A low cost biopolymeric material, poly [β-（1-4）-2-amino-2-deoxy-D-glucopyranose] （β-PADG） obtained from deacetylated chitin was used as stabilizer to synthesize zero valent nickel （ZVNi） nanoparticles. The β-PADG-ZVNi nanocomposite was characterized using infra red （IR）, UV-Vis spectrophotometric techniques and Scanning Electron Microscope （SEM）. The morphology of the composite showed that β-PADG stabilized-ZVNi nanoparticles were present as discrete particles. The mean particle size was estimated to be （7.76 ± 2.98） nm and surface area of 87.10 m2/g. The stabilized-ZVNi nanoparticles exhibited markedly greater reactivity for reduction of nitrate in water with 100% conversion within 2 hr contact owing to less agglomeration. Varying the β-PADG-to-ZVNi ratio and the ZVNi-to-nitrate molar ratio generally led to a faster nitrate reduction. About 3.4-fold difference in the specific reaction rate constant suggests that the application of the β-PADG-stabilizer not only increased the specific surface area of the resultant nanoparticles, but also greatly enhanced the surface reactivity of the nanoparticles per unit area.

Enhancing diaphragmatic defect repair and regeneration:How biomaterials leading the way to progress?

Physicians encounter significant challenges in dealing with large diaphragmatic defects in both pediatric and adult populations.Diaphragmatic hernias,such as Morgagni,Bochdalek,and Hiatus hernias,can result in congenital lesions that are often undiagnosed until the appearance of symptoms(bleeding,anemia,and acid reflux).Therefore,substantial potential exists for developing tissue-engineered constructs as novel therapeutic options in clinics.Recent research indicates promising mid-term performance for both natural and synthetic materials.However,studies exploring their application in diaphragm regeneration are limited and remain in the early research stages.Additionally,further investigation is required to address the constraints in human tissue supply for clinical implementation.This article comprehensively reviews the role of biomaterials in diaphragmatic tissue repair and regeneration.It emphasizes biomaterials,including biomimetic polymers used in technological solutions.This summary will enable researchers to critically assess the capability of existing natural biomaterials as essential tissueengineered patches for clinical use.

POLYETHYLENE CROSSLINKED WITH ULTRAVIOLET LIGHT

It was first proposed by Oster in 1956 that polyethylene could be crosslinked with ultraviolet fight in the presence of some photosensitizers. But the photocrossfinking method was not used in industry for a long period because the penetration of the light is limited. The recent work done by Rnby et al. is outstanding in the improvement on this method, and it is competitive to the high-energy irradiation method and the thermalchemistry method. Therefore, the photocrosslinking has a promising prospect in application now. This note is a brief introduction to the results about the theoretical analysis and