Effect of organoclay on the physical properties of UV-curable coatings

The combination of UV-curing and nanocomposite technology has been studied to produce cost-effective coatings with superior physical and mechanical properties. The clay was modified with dimethyl dihydrogenated-tallow quaternary ammonium salt and made organophilic. The effect of the organoclay(2-10 phr) on curing rate, mechanical, thermal and physical properties of a urethane-acrylate coating has been determined. X-ray diffraction analysis, AFM, SEM and TEM images as well as the tensile properties of different formulations have confirmed the uniform distribution of organoclay in polymer matrix. At 3 phr organoclay addition, the UV-cured film exhibited the best mechanical performance due to the formation of both intercalated and exfoliated morphologies. Curing time was reduced and the initial thermal decomposition temperature shifted 50°C to higher temperature by the incorporation of small amount of organoclay. The nanocomposite coating was also found to be more resistant against scratching compared with clay-free coating

Transparent low-density polyethylene/starch nanocomposite films

Low-density polyethylene (LDPE)/starch nanocomposite films were prepared by melt extrusion process. The first step includes the preparation of starchclay nanocomposite by solution intercalation method. The resultant product was then melt mixed with the main matrix, which is LDPE. Maleic anhydride-grafted polyethylene (MAgPE), produced by reactive extrusion, was used as a compatibilizer between starch and LDPE phases. The effects of using compatibilizer, clay, and plasticizers on physico-mechanical properties were investigated. The results indicated that the initial intercalation reaction of clay layers with starch molecules, the conversion of starch into thermoplastic starch (TPS) by plasticizers, and using MAgPE as a compatibilizer provided uniform distribution of both starch particles and clay layers, without any need of alkyl ammonium treatment, in LDPE matrix. The nanocomposite films exhibited better tensile properties compared to clay-free ones. In addition, the transparency of LDPE film did not significantly change in the presence of TPS and clay particles

Comparison of melt extrusion and thermokinetic mixing methods in poly(ethylene terephthalate)/montmorillonite nanocomposites

The scope of this study consists in studying the effects of processing type on thermal stability of poly(ethylene terephthalate) (PET) and its nanocomposites prepared with organically modified clays. To achieve this goal, an intercalating agent was synthesized and montmorillonite type of clay modified with this intercalating agent was mixed with the PET by using melt extrusion and high-shear thermokinetic mixing method. According to the results, manganese in the raw claythough chemically boundwas found to be responsible for the decreased intrinsic viscosity (IV) values, i.e. decreased molecular weight in PET/organoclay nanocomposites. Besides, it was revealed that working on the thermokinetic mixer provided substantial contributions such as shorter processing times in comparison to the melt extrusion method, elimination of drying step before melt processing, which has been accepted as an inevitable process for PET so far, less thermal degradation because of short processing times, and more homogeneous and better dispersion of the clay particles in PET matrix phase

A study of fibre breakage during compoundings short glass fibre reinforced composites

26th Annual Meeting of Polymer Processing Society Banff, Canad

Characterization of Fiber Break-up During Compounding of Glass Fiber-Reinforced Polyamide

Regional Meeting of Polymer Processing Society Istambul, Turqui

A matricial approach of fiber break-up in twin screw extrusion of glass fibers reinforced thermoplastics

27th Annual Meeting of Polymer Processing Society, Marrakech (Maroc), 10-14 mai 201

A matricial approach of fibre breakage in twin-screw extrusion of glass fibres reinforced thermoplastics

International audienceLimiting fibre breakage during composite processing is a crucial issue. The purpose of this paper is to predict the evolution of the fibre-length distribution along a twin-screw extruder. This approach relies on using a fragmentation matrix to describe changes in the fibre-length distribution. The flow parameters in the screw elements are obtained using the simulation software Ludovic®. Evolution of an initial fibre-length distribution for several processing conditions was computed and the results were compared with experimental values. The computation gives satisfying results, even though more comparisons with experiments would be necessary

Influence of extrusion conditions on fiber breakage along the screw profile during twin screw compounding of glass fiber-reinforced PA

International audienceIn the present study, Polyamide 12 was compounded with glass fibers in both laboratory and industrial twin screw extruders using various processing conditions (screw speed and feed rate). Dead-stop experiments were performed and samples were collected at different locations along the screws in order to determine the fiber length distribution and the extent of fiber breakage. Results show that significant fiber break-up occurs right after the addition of glass fibers to the molten matrix. Similarly fiber length distribution changes drastically at the first sampling location, near the glass fiber feeder. Processing conditions also influence the extent of degradation: it increases with screw speed and decreases with feed rate, which controls the residence time. Flow modelling has been used to calculate the flow conditions along the screw profile. It is shown that the modified Shon-Liu-White model previously proposed to describe the average fiber length evolution as function of specific energy is not able to correctly predict the evolution along the screw profile. In similar processing conditions, the large industrial extruder appears as less severe than the small laboratory on

Correlation between processing conditions and fiber breakage during compounding of glass fiber-reinforced polyamide

International audienceThe inter-relationship between processing conditions and fiber breakage has been studied for glass fiber-reinforcedpolyamide 12, prepared using (i) an internal batch mixer, (ii) a laboratory scale corotating twin screw extruder, and (iii) an industrial scale twin screw extruder. The average fiber lengths and fiber length distributions were measured for various compounding conditions (screw or rotor speed, mixing time, feed rate). Experimental results have shown that fiber breakage depends on both screw speed and mixing time, the later being controlled, in an extruder, by the feed rate. For a given compounding system (batch mixer or twin screw extruder), the energy input (specific mechanical energy, SME) during the compounding process is found to be a reliable parameter, which governs fiber length (average, minimal, and maximal) evolution. Experimental data are correctly described with a model defining change in fiber length as a function of SM