Effects of different production processing stages on mechanical and surface characteristics of polylactic acid and PET fibre fabrics

This paper reports study on the polylactic acid (PLA) and polyester (PET) knitted fabrics mechanical and surface characteristics at low-stress and the influence of typical commercially applied different production processing stages on the properties. The KES-FB is used for the investigation of low-stress bending, compression, tensile, shear and surface characteristics. The results show remarkable changes after each processing stage, such as scouring, drying, dyeing, heat setting and softening, in mechanical and surface characteristics of PLA and PET fibre knitted fabrics. PLA knitted fabrics represent higher values in bending, shear and surface properties after different processing stages as compared to PET knitted fabrics. The values of bending rigidity (B), bending hysteresis (2HB), shear stiffness (G), and shear hysteresis (2HG and 2HG3) have been significantly decreased after the scouring treatment. There is a considerable decrease in B, 2HB, G, 2HG and 2HG3 values and an improvement in tensile elongation (EMT) after dyeing of PET and PLA fabrics. A slight reduction in shear and bending properties of polylactic acid fibre fabrics shows that softening treatment decreases the inter fibre and inter yarn friction. LT (linearity of load-extension curve), RT (recovery from tensile deformation), LC (linearity of compression curve) and RC (recovery from compression deformation) properties are not found quite sensitive for different production processing stages in case of both the fabrics

Protein-based nanoformulations for α-Tocopherol encapsulation

Nanoparticles of bovine serum albumin (BSA) and silk fibroin (SF) with entrapped α-tocopherol were produced via ultrasonic emulsification. Populations with particle size of 200300 nm and highly negatively charged were obtained for all the tested formulations. Entrapment efficiencies of around 99% revealed the effective encapsulation of α-tocopherol into the produced nanoformulations. Generally, these nanodevices did not induce significant cytotoxicity to human skin keratinocytes for all the concentrations tested. The developed formulations showed free radical scavenging of ABTS.+ ability resulting from the synergistic effect between proteins in formulation and the entrapped tocopherol. Overall, the results contribute for the establishment of BSA:VO and BSA:SF:VO as biodegradable and non-toxic nanoformulations for the functionalization of textile devices and controlled delivery of tocopherol into the skin.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE2020 (POCI-01-0145FEDER-006684) and BioTecNorte operation (NORTE-01-0145FEDER-000004) funded by European Regional Development Fund under the scope of Norte 2020-Programa Operacional Regional do Norte. Artur Ribeiro thanks FCT for the SFRH\BPD\98388\2013 grant. Fatemeh Shahmoradi would like to acknowledge the Iran Ministry of Science, Research and Technology (MSRT) for the monetary support.info:eu-repo/semantics/publishedVersio

Fabrication of a silica aerogel and examination of its hydrophobic properties via contact angle and 3M water repellency tests

Aerogels are dry gels with a very high specific pore volume. Aerogels with increased hydrophobicity have significant potential to expand their use as lightweight materials. Considering its special nanostructure and exceptional properties, this paper focuses on the synthesis and hydrophobic evaluation of a silica aerogel. The structural properties were investigated by measuring density, SEM micrographs, and BET analyses. Also, the hydrophobic evaluation was carried out by measuring 3M water repellency and water/alcohol contact angle. The BET analysis showed successful synthesis of the nanoporous silica aerogel with a pore size of 24 nm and porosity of 89%. The synthesized aerogel showed 3M water repellency of 3 and water contact angle of 129.6˚. Also, it is worth-mentioning that as the alcohol content of the drops in 3M water repellency test is increased, the drop contact angle is decreased due to its lower surface tension. Thus, the contact angle reaches the zero at 3M water repellency test number of 4 (water/alcohol 60/40)

Effects of different production processing stages on mechanical and surface characteristics of polylactic acid and PET fibre fabrics

31-37This paper reports study on the polylactic acid (PLA) and polyester (PET) knitted fabrics mechanical and surface characteristics at low-stress and the influence of typical commercially applied different production processing stages on the properties. The KES-FB is used for the investigation of low-stress bending, compression, tensile, shear and surface characteristics. The results show remarkable changes after each processing stage, such as scouring, drying, dyeing, heat setting and softening, in mechanical and surface characteristics of PLA and PET fibre knitted fabrics. PLA knitted fabrics represent higher values in bending, shear and surface properties after different processing stages as compared to PET knitted fabrics. The values of bending rigidity (B), bending hysteresis (2HB), shear stiffness (G), and shear hysteresis (2HG and 2HG3) have been significantly decreased after the scouring treatment. There is a considerable decrease in B, 2HB, G, 2HG and 2HG3 values and an improvement in tensile elongation (EMT) after dyeing of PET and PLA fabrics. A slight reduction in shear and bending properties of polylactic acid fibre fabricsshows that softening treatment decreases the inter fibre and inter yarn friction. LT (linearity of load-extension curve), RT (recovery from tensile deformation), LC (linearity of compression curve) and RC (recovery from compression deformation) properties are not found quite sensitive for different production processing stages in case of both the fabrics

Effects of finishing on the mechanical and thermal properties of fabrics from wool and hollow polyester fibres

The effects of finishing steps on hollow and solid polyester/wool have been studied in order to establish the processing behaviour and performance characteristics of fabrics from these fibres. The effect of hollow fibres on fabric tensile strength, pilling, and crease recovery were studied. In addition, the water vapour permeability, air permeability, thermal properties and fabric handle were investigated. The results show that finishing has no adverse effects on fabric strength. By using hollow fibres in the fabrics, the extent of pilling was reduced. Among the different steps of finishing, scouring has the most significant effect on fabric hand due mainly to the large reduction in both bending, and shear rigidity and hysteresis. The results on crease recovery, water vapour permeability and air permeability revealed that the fabric properties are more affected by the fabric structure than the type of polyester fibre. In addition, while the hollow fibre fabrics always have lower thermal conductivity than similar fabrics with solid polyester fibres, their thermal properties are greatly affected by the dyeing process. </jats:p