THE EPOXY NANOCOMPOSITES WERE PREPARED THROUGH IN SITU DISPERSION OF DIFFERENT ALUMINA NANOPARTICLES DURING EPOXY POLYMERIZATION. ACCORDING TO DMTA ANALYSIS, THE ORGANICALLY MODIFIED NANOSIZED ALUMINA PARTICLES RESULTED TO HIGHER GLASS TRANSITION TEMPERATURE (TG) AND HIGHER DAMPING AREA FOR THE EPOXY NANOCOMPOSITES. THE INCREASE IN TG MAY BE ATTRIBUTED TO CHAIN IMMOBILITY DUE TO EFFECTIVE DISPERSION OF ALUMINA NANOPARTICLES. THE HIGHER DAMPING AREA IN LOSS FACTOR CURVES INDICATE FOR ALUMINA ABILITY IN CRACK DEFLECTION AND HENCE IMPROVING FRACTURE TOUGHNESS.

IN THIS PAPER, THE AMOUNT OF POROSITY FOR COMPOSITE SCAFFOLDS BASED ON GELATIN AND HYDROXYAPATITE (HA) FABRICATED FOR BONE TISSUE ENGINEERING APPLICATIONS WAS EVALUATED AND BENDING MODULI OF SUCH SCAFFOLDS WERE STUDIED USING DYNAMIC MECHANICAL THERMAL ANALYSIS (DMTA) METHOD. ALL THE SAMPLES EXHIBITED POROSITIES HIGHER THAN 42% (FOR 50 WT% HA) UP TO 72% AS MAXIMUM LEVEL (FOR PURE GELATIN). BENDING MODULI OF ALL THE SAMPLES WERE OVER 35 GPA (RANGING FROM 36 TO 38 GPA) BEING SUPERIOR TO THOSE REPORTED EARLIER IN THE LITERATURE FOR OTHER BIODEGRADABLE BIOMATERIALS USED IN BONE TISSUE ENGINEERING SUCH AS SR-PGA AND PLLA/HA COMPOSITES.

A MODEL POLY (METHYL METACRYLATE-CO-BUTYL ACRYLATE) PRESSURE SENSITIVE ADHESIVE CONTAINING 30 WT% OF METHYL METACRYLATE (MBC30) WAS ANALYZED RHEOMECHANICALLY AS A FUNCTION OF ANNEALING TIME. THE EXTRACTED G’ AND G” CURVES FROM DYNAMIC MECHANICAL THERMAL ANALYSIS UNDER APPLIED SHEAR LOAD AT FREQUENCY OF 1 HZ AND STRAIN AMPLITUDE OF 1% REPRESENTED THE BEHAVIOR OF HIGHLYFILLED ELASTOMERS, PAYNE EFFECT, PROBABLY DUE TO ITS NANOSTRUCTURING. THE GLASS TRANSITION TEMPERATURE OF BUTYL ACRYLATE-RICH AND METHYL METHACRYLATE-RICH COPOLYMERS SHIFTED AS MUCH AS 50OC AND 10OC IN COMPARISON TO THEIR CORRESPONDING RESULTS FROM DIFFERENTIAL SCANNING CALORIMETRY, -26OC AND 160OC, RESPECTIVELY. LONG-TERM STORAGE OF MODEL ADHESIVE FILM AT ABOVE ITS GLASS TRANSITION TEMPERATURE (ANNEALING) AFFECTED ITS STRUCTURE THROUGH ITS MOLECULAR HOMOGENIZATION.

THE EFFECT OF SURFACE FRICTION COEFFICIENT AND MOLECULAR ELASTIC RECOVERY ON THE SCRATCH SURFACE DAMAGE OF PP/WOLLASTONITE COMPOSITES WAS INVESTIGATED. SCRATCH CONTOUR LENGTH AND SCRATCH SURFACE WERE CONSIDERED AS ACCEPTABLE CRITERIA TO EVALUATE THE SCRATCH RESISTANCE. THEREFORE, BY USING IMAGE ANALYZING TECHNIQUE AND SCANNING ELECTRONIC MICROSCOPY (SEM), SCRATCH RESISTANCE OF SAMPLES WERE CHARACTERIZED. THE VISCOELASTIC PROPERTIES OF SAMPLES WERE COMPARED USING DMTA TESTS. THE RESULT OBTAINED SHOWN THAT WOLLASTONITE IMPROVES SCRATCH RESISTANCE OF PP. REDUCTION OF THE FRICTION COEFFICIENT OF SCRATCH SURFACE IMPROVES THE SURFACE DAMAGE, AND SCRATCH VISIBILITY. ALSO ADDITION OF PE REDUCES SIGNIFICANTLY THE SCRATCH VISIBILITY AND DISAPPEARING SCRATCH SURFACE DAMAGE BECAUSE INCREASING THE ELASTIC RECOVERY.

THIS PAPER CONSIDERS THE EFFECTS OF ADDING MICROCAPSULES ON THE MECHANICAL PROPERTIES OF A SELF-HEALABLE EPOXY COATING. MECHANICAL PROPERTIES OF EPOXY SAMPLES CONTAINING VARIOUS WT % OF MICROCAPSULES WITH MEAN DIAMETER OF 28- 116 MM WERE EVALUATED USING TENSILE STRENGTH MEASUREMENTS AND DMTA. THE RESULTS SHOWED THAT THE ADDITION OF MICROCAPSULES REDUCES THE TENSILE PROPERTIES OF THE COATING, THE EXTENT OF WHICH DEPENDS ON THE MICROCAPSULE SIZE AND LOADING WT %.

IN THIS RESEARCH COPOLYMERS OF 4-CHLOROMETHYL STYRENE (CMS) WITH DIFFERENT MONOMERS SUCH AS STYRENE (ST), METHYL ACRYLATE (MA), ETHYL ACRYLATE (EA), METHYL METHACRYLATE (MMA), BY FREE RADICAL POLYMERIZATION METHOD AT 70±1OC USING A, A’-AZO BIS (ISOBUTYRO NITRILE) (AIBN) AS AN INITIATOR WERE SYNTHESIZED. [1, 2] THEN COPOLYMERS OF 4- CHLORO METHYL STYRENE HAVE BEEN MODIFIED BY 2-AMINO BENZOIC ACID GROUPS THROUGH THE SUBSTITUTION REACTION OF THE BENZYLIC CHLORIDE. THE POLYMERS, OBTAINED IN QUANTITATIVE YIELDS, WERE CHARACTERIZED BY FT-IR, 1HNMR SPECTROSCOPY AND DYNAMIC MECHANICAL THERMAL ANALYSIS (DMTA). ALL THE COPOLYMER CONTAINING 2-AMINO BENZOIC ACID GROUPS SHOWED A HIGH GLASS TRANSITION TEMPERATURE (77OC) RESPECTIVELY IN COMPARISON WITH PRIMARY COPOLYMERS (IN THE RANGE 37OC). THE INCREASE OF THE GLASS TRANSITION TEMPERATURE REFLECTS THE SUBSTANTIAL INCREASE IN RIGIDITY OF NEW COPOLYMERS BEARING BULKY SUBSTITUENT’S IN SIDE CHAINS.

THIS PAPER CONSIDERS THE EFFECTS OF SIMULTANEOUS ADDITION OF MICROCAPSULES AND NANOPARTICLES ON THE MECHANICAL PROPERTIES OF A SELF-HEALABLE EPOXY COATING. A MODEL NANO-COMPOSITE COATING WAS PREPARED VIA ADDITION OF 1 WT% APS TREATED NANO-ZRO2 AND 1 WT % NANO-CLAY PARTICLES TO EPOXY RESIN. 5 WT % LINSEED OIL-FILLED MICROCAPSULES WITH AVERAGE DIAMETER OF 72 ΜM WERE ADDED INTO THE EPOXY RESIN. MECHANICAL PROPERTIES OF THE PREPARED SAMPLES CONTAINING NANOPARTICLES AND MICROCAPSULES WERE EVALUATED VIA TENSILE STRENGTH MEASUREMENTS AND DMTA.