Effect of Superficial Scratch Damage on Tension Properties of Carbon/Epoxy Plain Weave Laminates

The effect of scratch damage on the tension properties of carbon fiber plain weave laminates has been studied in detail using digital image correlation (DIC) and acoustic emission (AE). A range of scratch lengths was machined onto different laminates. The bearing capacity of the laminates was then compared with that of unaltered samples. The strain field distributions near the scratches were measured and analyzed as a function of scratch length with DIC. Initiation and propagation of damage were monitored during the tensile tests using AE. Failure sites and morphologies were observed and analyzed. The results show that superficial scratches have little effect on the strength of plain weave laminates when the scratch length is less than 80% of the specimen width. Scratches affect the distribution of strain near the scratch but not far away from the scratch or at the back face of the sample. Not all samples broke from the scratch site but instead broke from the free edge of the sample or close to the gripping region.

Transformation of Pectins into Non-Ionic or Anionic Surfactants Using a One-Pot and Cascade Mode Process

The present article describes the one-pot synthesis of double- and single-tailed surfactants by a cascade process that involves the hydrolysis/butanolysis of pectins into butyl galacturonate monosaccharides followed by transesterification/transacetalisation processes with fatty alcohols, and subsequent aqueous basic and acid treatments. The cascade mode allows the depolymerisation to proceed more efficiently, and the purification conditions are optimised to make the production of single-tailed surfactants more manufacturable. These products in a pure form or as mixtures with alkyl glycosides resulting from butanolysis and transglycosylation of pectin-derived hexoses, exhibit attractive surface-tension properties, especially for the n-oleyl ᴅ-galactosiduronic acid products. In addition, a readily biodegradability and an absence of aquatic ecotoxicity are shown for the galacturonic acid derivatives possessing an oleyl alkyl chain at the anomeric position.

Dissolution and Surface Tension Properties of Ethanol-Wash Solute Obtained from Industrial Sunflower Meal

Sunflower meal ethanol-wash solute (SEWS) is one of the products obtained from a procedure for the complete valorization of industrial sunflower meal. The meal was subjected to a 4-step treatment with aqueous ethanol solution (75%) followed by vacuum concentration and lyophilization of spent ethanol wash liquids to generate powdery SEWS. The purpose of this study was to evaluate surface tension and dissolution of SEWS in water in response to two variables, concentration (0.1%, 0.3%, 0.5%) and temperature (20°C, 30°C, 40°C, 50°C). The rate constants of 0.1% and 0.3% SEWS dissolution increased in response to temperature elevations up to 40°C. For both concentrations, the dissolution at 50°C was slowed down, which resulted in deviations of the Arrhenius plot from linearity. No linear fit between rate constants and temperature increase for 0.5% SEWS was established. The addition of SEWS decreased the surface tension of pure water at all three concentrations. The most profound effect was observed at 50°C where water's surface tension (67.14 mN/m) was reduced 1.81-fold (37.35 mN/m) after adding 0.5% SEWS. Acquired characteristics are a valuable part of the SEWS's applicable profile needed for the potential use of the product in the food, nutraceutical, or agricultural industries.

Structure Property Investigation of Glass-Carbon Prepreg Waste-Polymer Hybrid Composites Degradation in Water Condition

The limited shelf life of carbon prepreg waste (CPW) from component manufacturing restricts its use as a composite reinforcement fibre on its own. However, CPW can be recycled with glass fibre (GF) reinforcement to develop a unique remediate material. Therefore, this study fabricated (1) a glass fibre-carbon prepreg waste reinforced polymer hybrid composite (GF-CPW-PP), (2) a polypropylene composite (PP), (3) a carbon prepreg waste reinforced composite (CPW-PP), and (4) a glass fibre reinforced composite (GF-PP) and reported their degradation and residual tension properties after immersion in water. The polymer hybrid composites were fabricated via extrusion technique with minimum reinforce glass-carbon prepreg waste content of 10 wt%. The immersion test was conducted at room temperature using distilled water. Moisture content and diffusion coefficient (DC) were determined based on water adsorption values recorded at 24-h intervals over a one-week period. The results indicated that GF-PP reinforced composites retained the most moisture post-168 h of immersion. However, hardness and tensile strength were found to decrease with increased water adsorption. Tensile strength was found to be compromised since pores produced during hydrolysis reduced interfacial bonding between glass fibre and prepreg carbon reinforcements and the PP matrix.