•Thermoplastic starch offers partial miscibility with PLA as evidenced by FESEM.•The addition of 4–6phr MLO leads to an elongation at break of 140–160%.•MLO also provides a compatibilization effect.
...In this work, poly(lactic acid), PLA and thermoplastic starch, TPS blends (with a fixed content of 30wt.% TPS) were prepared by melt extrusion process to increase the low ductile properties of PLA. The TPS used contains an aliphatic/aromatic biodegradable polyester (AAPE) that provides good resistance to aging and moisture. This blend provides slightly improved ductile properties with an increase in elongation at break of 21.5% but phase separation is observed due to the lack of strong interactions between the two polymers. Small amounts of maleinized linseed oil (MLO) can positively contribute to improve the ductile properties of these blends by a combined plasticizing-compatibilizing effect. The elongation at break increases over 160% with the only addition of 6phr MLO. One of the evidence of the plasticizing-compatibilizing effect provided by MLO is the change in the glass transition temperature (Tg) with a decrease of about 10°C. Field emission scanning electron microscopy (FESEM) of PLA-TPS blends with varying amounts of maleinized linseed oil also suggests an increase in compatibility.
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•Maleinized hempseed oil (MHO) increases toughness of polylatcide (PLA).•MHO increases thermal stability of PLA.•MHO contributes to high environmentally friendly PLA formulations.•MHO ...minimizes cold crystallization of PLA.•MHO gives balanced mechanical resistance and ductility to PLA.
The present study describes the effect of maleinized hemp seed oil (MHO) on the physical performance of polylactide (PLA) pieces. To this end, PLA pieces with varying MHO contents in the 0–10 wt% range were manufactured by twin-screw extrusion (TSE) followed by injection molding. The resultant pieces were characterized in terms of their mechanical, thermal, and thermomechanical properties. The obtained properties suggested that, unlike typical plasticizers, MHO does not only induce an increment in elongation at break and impact resistance but it also enhances both elastic modulus and tensile strength. In addition, a moderate decrease in the glass transition temperature (Tg) was observed. This was ascribed to simultaneous linear chain-extension, branching, and/or cross-linking phenomena due to the reaction of the multiple maleic anhydride (MAH) groups present in MHO with the terminal hydroxyl groups of the PLA chains. Furthermore, morphology characterization revealed that, though certain phase separation occurred at its highest content, MHO was finely dispersed as submicron droplets within the PLA matrix contributing to improving toughness. The use of multi-functionalized reactive vegetable oils thus represents a highly sustainable solution to reduce the intrinsic brittleness of PLA materials without compromising their mechanical resistance and the toughened biopolymer pieces described herein can find interesting applications in, for instance, rigid packaging.
•Calcium carbonate from seashell is an attractive bio-filler in polymeric industry.•We examine composition and thermal properties of calcium carbonate from seashell.•Used with eco-friendly epoxy ...matrices provides a high renewable content material.•Addition of 30wt.% of seashell bio-filler increase of over 50% in flexural modulus.•Calcium carbonate from seashell leads higher thermal stability materials.
The seashells, a serious environmental hazard, are composed mainly by calcium carbonate, which can be used as filler in polymer matrix. The main objective of this work is the use of calcium carbonate from seashells as a bio-filler in combination with eco-friendly epoxy matrices thus leading to high renewable contents materials. Previously obtaining calcium carbonate, the seashells were washed and grinded. The powder obtained and the resin was characterized by DSC, TGA, X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), and rheology plate-plate. The results show that addition of 30wt.% of seashell bio-filler increase mechanical properties as flexural modulus (over 50%) and hardness Shore D (over 6%) and thermal properties as an increase around 13% in glass transitions temperature. The results show that the addition of calcium carbonate from seashells is an effective method to increase mechanical properties of bio-composite and to reduce the residue of seashells from industrial production.
Different amounts of epoxidized linseed oil (ELO) have been added to poly(lactic acid)-PLA composites with hazelnut shell flour (HSF) to provide a plasticizing effect and improve the low intrinsic ...ductile properties of PLA/HSF composites. Mechanical, thermal, thermo-mechanical and dynamic mechanical properties have been studied in terms of the weight percentage ELO. Mechanical resistant properties in both tensile and flexural tests decrease with wt.% ELO while a remarkable increase with wt.% ELO is obtained. These results reveal a clear plasticization effect of ELO but, in addition, internal structure of PLA/HSF/ELO composites shows good PLA-HSF (matrix-particle) interactions so that indicating that ELO also provides a coupling effect between PLA matrix and HSF filler. ELO addition leads to a decrease in storage modulus (G′) obtained by dynamic mechanical thermal analysis (DMTA) in torsion mode thus giving clear evidence of the plasticization effect of ELO. Overall, the use of ELO in PLA/HSF composites is an attracting way to improve the low intrinsic fragility of these green composites; furthermore, ELO provides an improvement on thermal stability and a coupling effect between the polymer matrix and the surrounding lignocellulosic filler.
This works aims at the development thermosetting resins derived from epoxidized linseed oil (ELO) of high biobased content, by using a mixture of crosslinking agents, i.e. methyl nadic anhydride ...(MNA) and maleinized linseed oil (MLO). By using only MNA as crosslinking agent, the obtained resins are characterized by high stiffness and, consequently, high fragility. When MLO content increasing in the crosslinking mixture, up to 25 wt%, a decrease in mechanical resistant and thermomechanical is detected, thus indicating that MLO can provide flexibility to ELO-based thermosetting resins which is an interesting issue to obtain tailored properties by selecting the appropriate mixture composition. In general, the thermosetting resin crosslinked with 10 wt% MLO and 40 wt% MNA gives balanced properties together with noticeable biobased content, thus broadening the potential of these materials for uses in green composites and coatings.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The application of vegetable oils as novel plasticizers for poly(vinyl chloride) (PVC) is currently in the spotlight of the polymer industry due to their ingrained sustainability. In this study, ...novel vinyl plastisol/wood flour composites based on epoxidized linseed oil (ELO) were evaluated. For this, PVC was first plasticized by 70 parts by weight of ELO per hundred parts of resin (phr) to form a vinyl plastisol. Wood flour, obtained by dry grinding from reed (Phragmite communis), was then incorporated at five different loadings (10, 15, 20, 25, and 30wt.‐%) and three particle sizes (100, 250, and 500μm). The effect of ultraviolet (UV) radiation was explored to activate the surface of wood flour to increase its interfacial adhesion with the vinyl plastisol. Stereomicroscopy and scanning electron microscopy (SEM) were used to examine the composites fracture and determine the dispersion of wood flour in the vinyl matrix. As per the surface appearance and mechanical results, optimal materials were observed for vinyl plastisol composites at high contents of wood flour with the largest particles that were previously exposed to UV for 4min. Resultant renewable vinyl plastisol composites show a great deal of potential as designed materials for wood replacement in building applications.
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•Renewable vinyl plastisol composites based on epoxidized linseed oil (ELO) were developed by introducing reed wood flour•Optimal materials were observed for vinyl plastisol composites containing 20 to 30 wt.-% of wood flour particles of 500μm•Wood flour was exposed to ultraviolet (UV) radiation to increase its interfacial adhesion with the vinyl plastisol•Ductility of the vinyl plastisol composites prepared with UV-exposed wood flour for 4min increased up to 3.5times.
Poly(lactic acid), PLA, is a polyester that can be produced from lactic acid derived from renewable resources. This polymer offers attracting uses in packaging industry due to its biodegradability ...and high tensile strength. However, PLA is quite brittle, which limits its applications. To overcome this drawback, PLA was plasticized with epoxy-type plasticizer derived from a fatty acid, octyl epoxy stearate (OES) at different loadings (1, 3, 5, 10, 15, and 20 phr). The addition of OES decreases the glass transition temperature and provides a remarkable increase in elongation at break and impact-absorbed energy. Plasticizer saturation occurs at relatively low concentrations of about 5 phr OES; higher concentration leads to phase separation as observed by field emission scanning electron microscopy (FESEM). Optimum balanced mechanical properties are obtained at relatively low concentrations of OES (5 phr), thus indicating the usefulness of this material as environmentally friendly plasticizer for PLA industrial formulations.
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