Ispitivanje mehaničkih osobina polivinil-hlorida sa dodatkom modifikovanog kalcita kao punioca

Abstract

U radu su prikazani rezultati ispitivanja mehaničkih osobina (zatezna čvrstoća, zatezno izduženje, prekidna čvrstoća i prekidno izduženje) na PVC mešavinama koje sadrže PVC (polivinil-hlorid), stabilizator, klizno sredstvo i punilac. Kao punilac korišćen je nemodifikovani kalcit i uzorci kalcita modifikovani stearinskom kiselinom suvim i mokrim postupkom. Rezultati ispitivanja su pokazali da PVC mešavina, koja sadrži kalcit modifikovan mokrim postupkom ima bolje mehaničke osobine od one mešavine koja sadrži kalcit modifikovan suvim postupkom. Tako je čvrstoća pri zatezanju PVC mešavine koja sadrži kalcit modifikovan sa 1,5% stearinske kiseline mokrim postupkom za 2,84% veća u odnosu na čvrstoću pri zatezanju PVC mešavine, koja sadrži kalcit modifikovan sa istim sadržajem stearinske kiseline, ali suvim postupkom.

In this study, mechanical properties of PVC mixtures (PVC, stabilizer, lubricant and filler) such as tensile strength, tensile elongation, breaking strength and breaking elongation were investigated. Unmodified calcite, as well as calcite modified by stearic acid, were used as fillers in wet and dry processes. The PVC mixtures containing the calcite modified by wet procedure had better mechanical properties compared to those with the calcite modified by the dry process. Tensile and breaking strength of the PVC mixture containing the calcite modified with 1.5% stearic acid using the wet process were higher for 2.8 and 5.2%, respectively, compared to the PVC mixture containing the calcite modified with the same amount of acid used in the dry process. The tensile strength difference between the mixtures increased with the increase of the concentration of used stearic acid up to 3%. The strength of PVC mixture with the calcite modified by the wet process was 3.1% higher compared to the mixture containing calcite modified by dry process. The results showed that the bonding strength between calcite and the adsorbed organic component affected tensile strength, tensile elongation and breaking strength of the PVC mixtures. The best filler was obtained by wet modification using 1.5% stearic acid solution that provided the formation of a stearate monolayer chemisorbed on calcite. The PVC mixtures containing the calcite modified by wet process using 1.5% stearic acid solution exhibited the best mechanical properties. This calcite was completely hydrophobic with dominant chemically adsorbed surfactant, which means that stearate chemisorbed on calcite provided stronger interaction in the calcite-stearic acid-PVC system.