Testes físico-mecânicos e físico-químicos do couro da tilápia vermelha Physical-mechanical and physical-chemical tests of red tilapia leather

Abstract

Realizaram-se testes físico-mecânicos e físico-químicos em couro de tilápia vermelha (Oreochromis spp.) a fim de testar a sua resistência. As amostras foram distribuídas em delineamento inteiramente ao acaso com dois tratamentos: no T1, procedeu-se à retirada do corpo-de-prova no sentido longitudinal e, no T2, à retirada do corpo-de-prova no sentido transversal. Para os testes de determinação da resistência à tração, alongamento e rasgamento progressivo, foi utilizado o dinamômetro EMIC, com velocidade de afastamento entre as cargas de 100 ± 20mm/min, em ambiente climatizado (± 23ºC e UR do ar de 50%), por 24 horas. A espessura do couro variou de 0,61 a 0,75mm, mas não houve diferença entre os sentidos analisados. O couro apresentou maior resistência à tração no sentido transversal, 25,89N/mm², (PPhysical-mechanical and physical-chemical tests were carried out on red tilapia leather. They were distributed in a completely randomized design with two treatments: T1 = longitudinal body of proof; T2 = transversal body of proof. It was used the EMIC dynamometer for the tests of resistance to traction and elongation and the progressive tearing, with the speed of 100±20mm/min away between the charges, in an acclimatized room (±23°C and relative humidity of 50%) during 24 hours. The thickness of the analyzed leathers ranged from 0.61 to 0.75mm, without differing between the analyzed ways. The leather demonstrated a higher resistance to traction in the transversal direction (25.89N/mm²) (P<0.01), when compared to the longitudinal one (14.20N/mm²). However, the elongation was significantly higher (P<0.05) in the longitudinal direction (80.8%) when compared to the transversal (62.6%). There was no significant difference for the progressive tearing between the treatments (longitudinal = 18.56N/mm; transversal = 21.90N/mm). The leather demonstrated a content of 3.8% of chromium oxide, 15.1% of grease, and pH and difference value of 3.5 and 0.5, respectively. The values in the resistance and physical-chemical tests shown by the leather indicate that it may be used for clothing and leather artifacts in general.

Keywords

• tilápia
• couro
• resistência
• qualidade
• fibras colágenas
• tilapia
• leather
• resistance
• quality
• collagen fibers