No abstract

Toddy palm fruit have an apparent density below 0.8 g/cm³ and offer an interesting lightweight construction potential in polylactide (PLA) composites reinforced with 37 mass-% fibres. Single fibre bundles show similar mechanical properties compared with coir: tensile strength of 240 MPa, Young´s modulus of 3.8 GPa and an elongation at break of 31%. However, density and diameter (~ 50 µm) of fruit fibre bundles are significantly lower. The compression moulded composites have a density of 0.9 g/cm³ and achieved an unnotched Charpy impact strength of 12 kJ/m², a tensile strength of 25 MPa, Young's modulus of 1.9 GPa and an elongation at break of 9%. Due to the high porosity of the composites and the different stress-strain behaviour of fibre and matrix the fibre-reinforcement potential could not be fully used. Maximum stress of the composite was reached at the elongation at break of the PLA-matrix (~2%) while the fibre achieved its maximum stress at an elongation of ~31%. After reaching the maximum stress of the composite, the fibres were pulled out from the matrix with low energy absorption, resulting in a decrease in stress and a limited reinforcement potential. Additionally, the study investigates whether an insect attack by the Asian fruit fly on the mesocarp has a significant influence on the mechanical fibre characteristics. The results have shown that only the rough surface of the fibre bundles is smoothed by insect infestation. The mechanical properties were not significantly affected. For this reason insect-infested fruits of the toddy palm, which are no longer suitable for food production, can be used for the production of sustainable composite materials.

In this research, utilizing of Arabica spent coffee ground oil was investigated for textile processing applications including scouring and reactive dyeing for cotton. The spent coffee ground oil was extracted using hexane and its chemical compositions were analyzed. The synthesized biosurfactant from spent coffee ground oil was investigated for use in cotton scouring. The results showed that the biosurfactant could well work as a scouring agent for cotton. Much better water absorption and reduced yellowness on cotton were achieved but higher applied concentration was needed as compared with the commercial wetting agent. It was also found that scouring efficiency of the biosurfactant could be promoted by adding alkali i.e. sodium carbonate, into a scouring bath, resulting in a satisfactory scouring level. A study on utilizing spent coffee ground oil in reactive dyeing process informs that by incorporating the oil into an aqueous dyebath to create oil/water dual-phase dyeing system, the dye exhaustion and color yield of Reactive Red 120 dye obtained on cotton could be enhanced without adding salt. This promotes a development of salt-free reactive dyeing process.

In this study, the coconut oil/water dual-phase dyeing system for developing salt-free reactive dyeing process for cotton was established. The selected dyes in this work were hot-dyeing reactive dyes, including C.I. Reactive Red 243, C.I. Reactive Blue 214 and C.I. Reactive Orange 70. A dual-phase dyeing system was performed under various coconut oil to water ratios and a comparative study was conducted on the conventional aqueous-based reactive dyeing in the presence and absence of salt. The results showed that the oil to water ratio of 3:1 imparted the highest colour yields (K/S values) and achieved a superior colour yield to the conventional aqueous-based dyeing. The results also pointed out that better dye fixation could be attained by dyeing cotton with the coconut oil/water dual-phase dyeing process under the optimum conditions. A comparable degree of dye exhaustion was observed for the aqueous-based and the dual-phase dyeing processes, however, the dye fixation was higher for the dual-phase dyeing, indicating less dye hydrolysis in this dyeing system. Consequently, superior colour fastnesses to washing and rubbing were obtained, less dye staining was observed in the case of dual-phase dyeing. A study on reusability of the coconut oil recovered from the spent dyebath for another reactive dyeing cycle was also conducted. The oil from the spent dyebath was directly taken to use without any further purification as a dual-phase medium along with water and the obtained result indicated a reusability potential of coconut oil. From this research, it infers that cleaner reactive dyeing process with the coconut oil/water dual-phase system for cotton could be developed.

Sulphatoethylsulphone reactive-disperse dye was synthesized via diazotization reaction of aminophenyl-4-(β-sulphatoethylsulphone) followed by coupling reaction of the diazonium salt with phenol as a coupling agent. The synthesized dye was well dyeable on both natural and synthetic fibers with providing orange shade on cotton, silk and nylon, while the dyed PLA and PET fibers appeared in yellow shade. The dyeing conditions for cotton and silk could be conducted using 60 g/l Na2SO4 and 20 g/l Na2CO3 at 60°C for 90 minutes whereas dyeing on PLA and PET fibers was optimally done at 110°C for 30 and 45 minutes for PLA and PET, respectively. In case of nylon, it could be dyed at 100°C for 15 minutes. The synthesized reactive-disperse dye could well dye on these 5 fibers with excellent color fastness to washing.