COMPATIBILISERS IN WOOD-POLYETHYLENE COMPOSITES AND THERE INFLUENCE ON THE MECHANICAL PROPERTIES AND WATER ABSORPTION
In this paper the improvement of the compatibilisation between wood particles and HDPE-matrix composites was investigated. A series of methods of compatibilisation and modification of the composite were performed and compared. The objective was to find the most suitable method for industrial up scaling, based on mechanical properties obtained. The tensile test of samples was performed, before and after water absorption investigation. Water absorption of composites was studied at two different temperatures: 25°C and 50°C. The water absorption kinetics was studied and it was found that water is absorbed in composites following the kinetics described by the Fick`s diffusion theory. After absorption, an important loss of properties was observed, due to the destruction of the wood structure due to the water absorbed.
Thermoplastics Reinforced with Wood Fillers: A Literature Review
Abstract Problems concerning the processing of thermoplastics reinforced with wood fillers are discussed. The high level of moisture absorption by the filler, its poor wettability, as well as the insufficient adhesion between untreated filler and the polymer matrix are reasons for the low tensile strength and high moisture sorption of composites. These shortcomings of composites can be prevented by the modification of the interface. The fiber-matrix compatibility and the composites properties can be improved by using some physical (e.g., steam explosion, corona, cold plasma) and chemical (cross-linking and acetylation of cellulose, grafting, use of coupling agents) methods. Modified wood-polymer interaction mechanisms are complex and specific for each definite system and processing conditions. Cellulose cross-linking and acetylation reduce hygroscopicity and swelling of wood and wood composites. Grafting of styrene to wood is effective for wood-polystyrene systems. The best coupling agent for wood-thermop...
Electrochemical detection of copper(II) at a gold electrode modified with a self-assembled monolayer of penicillamine
A penicillamine (PCA) self-assembled monolayer (SAM) was prepared on a gold electrode. It has been found that the modified electrode exhibited a selective response to copper ions. As demonstrated by cyclic voltammetric experiments, the SAM-based electrode showed an attractive ability to preconcentrate efficiently traces of copper(II) from solutions. Under optimum conditions, the anodic peak current was proportional to the concentration of Cu(II) in the range from 8.0 × 10−7 to 1.0 × 10−4 M with a detection limit of 4.0 × 10−7 M. Moreover, this modified gold electrode is also characterized by excellent repeatability, showing a relative standard deviation of 3.2% for nine successive measurements of 1.0 × 10−5 M Cu(II). The PCA/Au SAM gold electrode was used for the determination of Cu(II) in a tap water sample and the results showed a good agreement with the data obtained by atomic emission spectrometry.