Influence of size and percentage of wood particles on properties of wood-polymer composites

V zadnjih 10 letih je uporaba lesno plastičnih kompozitov wood plastic composites - WPC) za mnogo različnih izdelkov, tako za zunanjo kot tudi notranjo uporabo, zelo narasla. Proizvodnja le-teh poteka na več različnih načinov: izdelujemo jih npr. s stiskanjem, z ekstrudorjem, z vbrizgavanjem v kalup, itd.poleg tega pa lahko s spreminjanjem komponent v mešanici vplivamo na lastnosti kompozita. Z različnimi dodatki/primesmi kot so lepila, barvila, polnila, itd., lahko še dodatno vplivamo na lastnosti kompozita. Spreminjali smo velikosti lesnih iveri ter njihov delež, nato pa z različnimi testi ugotavljali, kako te spremembe vplivajo na lastnosti WPC-ja. Ugotovili smo, da lahko na mehanske in fizikalne lastnosti vplivamo tako z velikostjo iveri kot tudi z njihovim deležem. Z višjim deležem lesnih iveri in večjimi dimenzijami iveri izboljšamo mehanske lastnosti kot so: upogibna trdnost, modul elastičnosti in tlačna trdnosta s tem izgubimo na dimenzijski stabilnosti, nabreku in navzemu vode. Z višjim deležem lesa in večjimi frakcijami lesa omogočimo boljšo sorpcijo vode v notranjost kompozitazato sta delež in velikost iveri pomembna za specifične proizvode, glede na namen uporabe lesno plastičnega kompozita.In the past 10 years, wood plastic composites gained high rise of use for wide range of products for both interior and exterior. There are many different ways of their production, such as: pressing, extrude system, mold injection, etc. Next to different production systems we can also effect the properties of WPC by changing the material used in the mixture. With different additives we can influence the properties of the composite even more. We used different sizes and percentages of wood particles to build a composite. Then we performed different tests and monitored the influence of wood particles on properties of WPC. We found out that we can have influence on mechanical and physical properties with both variables. Using higher percentage and bigger sizes of wood particles we improve mechanical properties such as bending strength, module of elasticity and compressive strength, but we deteriorate the dimension stability, swelling and uptake of water. Using higher percentage and bigger wood particles we get better sorption of water in the interior of composite. That is why the percentage and particle size are very important for specific products regarding the purpose of use of a wood plastic composit