Preparation and Characterization of Tapioca Starch/Polycaprolactone/Clay Composites

In this work, plasticized tapioca starches (PTSs), blends of PTS and polycaprolactone (PCL), and composites of PTS/clay and PCL/PTS/clay were prepared by melt blending. Both natural clay (MMT) and octadecylamine modified clay (OMMT) were used in this study. OMMT was prepared by cation exchange reaction of Na+ cation in the interlayer of MMT with octadecylammonium cation from octadecylammonium chloride. X-ray diffraction (XRD) results showed that the OMMT has bigger d-spacing than that of original MMT indicating octadecylammonium cation has successfully intercalated into the clay interlayer. Thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, and elemental analysis also indicated the presence of octadecylammonium cation in the OMMT. PTSs were prepared by gelatinizing and plasticizing tapioca starch with water and glycerol, respectively in a Thermo Haake Polydrive internal mixer. Scanning electron micrographs showed that the tapioca starch formed a continuous phase after it was gelatinized and plasticized with water and glycerol. The study indicated that the tensile, thermal and water absorption properties of PTSs were strongly influenced by the contents of water and glycerol. The PTSs were water sensitive and exhibited low tensile properties. The formulation of tapioca starch, glycerol and water in the weight ratio of 5:1:4 was selected to study the effect of MMT, OMMT or PCL addition on its properties. The composites of PTS/clay were prepared by melt blending of PTS with various amount of MMT or OMMT also in a Thermo Haake Polydrive internal mixer. The XRD and TEM results showed that the composites produced are of intercalated types. Transmission electron micrographs revealed that MMT was better dispersed than that of OMMT in the PTS matrix due to the strong polar interaction between the hydrophilic MMT and PTS. Consequently, higher tensile strength, modulus, thermal stability and storage modulus were observed in PTS/MMT composites compared to those of PTS/OMMT composites as well as neat PTS. However the water resistance property of PTS was improved by the presence of OMMT. The blends of PCL and PTS were prepared by melt blending of PCL and PTS of different compositions also in a Thermo Haake Polydrive internal mixer. The presence of PCL improved the tensile strength, elongation at break, thermal stability and water resistance property of PTS. PCL/PTS/clay composites were also prepared by melt blending the blend and clays. XRD results showed that the composites produced are of intercalated types. Transmission electron micrographs revealed that OMMT was better dispersed than that of MMT in the matrix. Significant improvements in tensile strength (> 60%) and elongation at break (> 1000%) were observed by the addition of 1 php of OMMT. Improvement in water resistance property was also observed in PCL/PTS/OMMT composites. In contrast, no obvious properties improvements were observed for PCL/PTS/MMT composites

Enhancement of tensile strength and flexibility of Polycaprolactone/Tapioca starch blends by Octadecylamine modified clay.

Polycaprolactone/tapioca starch/octadecylamine modified clay (OMMT) nanocomposites were successfully prepared by melt blending. X-ray diffraction and transmission electron microscopy (TEM) of the products showed that they are nanocomposites of a mixture intercalated and exfoliated types. In addition, the TEM also revealed that the OMMTlayers are homogeneously distributed in the polymer matrix. The presence of 1 php of OMMT improved the compatibility of the polymers in the blends which consequently increased the tensile strength of the blend of more than 60% and elongation at break of more than 1,000%

Plasticized and nanofilled poly(lactic acid) nanocomposites: mechanical, thermal and morphology properties

Poly(lactic acid) (PLA)-based nanocomposites filled with graphene nanoplatelets (xGnP) and containing epoxidized palm oil (EPO) as plasticizer were prepared by melt blending method. PLA was first plasticized by EPO to improve its flexibility and thereby overcome its problem of brittleness. Then, xGnP was incoporated into plasticized PLA to enhance its mechanical properteis. Plasticized and naonofilled PLA nanocomposites (PLA/EPO/xGnP) showed improvement in the elongation at break by 61% compared with plasticized PLA (PLA/EPO). The use of EPO and xGnP increases the mobility of the polymeric chains, thereby improving the flexibility and plastic deformation of PLA. The nanocomposites also resulted in an increase of up to 26.5% in the tensile strength compared with PLA/EPO blend. PLA/EPO reinforced with xGnP shows that increasing the xGnP content triggers a substantial increase in thermal stability. The TEM image of PLA/EPO/xGnP shows that the xGnP was uniformly dispersed in the PLA matrix and no obvious aggregation is observed

Mechanical, thermal, and morphology properties of poly(lactic acid) plasticized with poly(ethylene glycol) and epoxidized palm oil hybrid plasticizer

Poly(lactic acid) (PLA) has received great attention recently due to its good physical and mechanical properties such as high tensile strength and modulus, good processability and biodegradability. In this study, low molecular weight poly(ethylene glycol) (PEG) and epoxidized palm oil (EPO) were used as hybrid plasticizers to improve toughness and ductility of PLA. Using the solubility parameter, a tentative evaluation of the hybrid plasticizer that could act as the most effective plasticizer for PLA has been performed and the obtained results have been corroborated with the materials physical properties. Excellent plasticizing effect was obtained by hybrid plasticizer PEG:EPO with ratio 2:1. Addition of PEG:EPO (2:1) hybrid plasticizer to PLA shows a significant improvement of 12,402%, compared to neat PLA. The improvement in flexibility and decrease in rigidity for the plasticized PLA is well evidenced by lower glass transition temperature (Tg) and tensile modulus values. In relation to the thermal stability, a decrease in thermal properties of the hybrid plasticized PLA was observed due to the volatility of the plasticizers. Scanning electron microscopy (SEM) shows that the hybrid plasticizer was turned PLA's smooth surface to fibrous structure and rough fracture surface

Enhancement of tensile strength of oil palm mesocarp fiber/poly(butylene succinate) biocomposite via superheated steam-alkali treatment of oil palm mesocarp fiber / Yoon Yee Then ... [et al.]

Natural fiber is incompatible with hydrophobic polymer due to its hydrophilic nature. Therefore, surface modification of fiber is needed to impart compatibility. In this work,superheated steam (SHS)-alkali was introduced as novel surface treatment method to modify oil palm mesocarp fiber (OPMF) for fabrication of biocomposites. The OPMF was first pre-treated with SHS and subsequently treated with varying NaOH concentration (1, 2, 3, 4 and 5%) and soaking time (1, 2, 3 and 4h) at room temperature. The biocomposites were then fabricated by melt blending of 70 wt% SHS-alkali treated-OPMFs and 30 wt% poly(butylene succinate) in a Brabender internal mixer followed by hot-pressed moulding. The combination treatment resulted in fiber with rough surface as well as led to the exposure ofmicrofibers. The tensile test result showed that fiber treated at 2% NaOH solution and 3h soaking time produced biocomposite with highest improvement in tensile strength (69%) and elongation at break (36%) in comparison to that of untreated OPMF

Enhancement of mechanical and thermal properties of polylactic acid/polycaprolactone blends by hydrophilic nanoclay.

The effects of hydrophilic nanoclay, Nanomer PGV, on mechanical properties of Polylactic Acid (PLA)/Polycaprolactone (PCL) blends were investigated and compared with hydrophobic clay, Montmorillonite K10. The PLA/PCL/clay composites were prepared by melt intercalation technique and the composites were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). FTIR spectra indicated that formation of hydrogen bond between hydrophilic clay with the matrix. XRD results show that shifting of basal spacing when clay incorporated into polymer matrix. TEM micrographs reveal the formation of agglomerate in the composites. Based on mechanical properties results, addition of clay Nanomer PGV significantly enhances the flexibility of PLA/PCL blends about 136.26%. TGA showed that the presence of clay improve thermal stability of blends. DMA show the addition of clay increase storage modulus and the presence of clay Nanomer PGV slightly shift two of blends become closer suggest that the presence of clay slightly compatibilizer the PLA/PCL blends. SEM micrographs revealed that presence of Nanomer PGV in blends influence the miscibility of the blends. The PLA/PCL blends become more homogeneous and consist of single phase morphology

Enhancement of tensile properties of surface treated oil palm mesocarp fiber/poly(butylene succinate) biocomposite by (3-aminopropyl)trimethoxysilane

The issue related to relatively poor interfacial adhesion between hydrophilic natural fiber and hydrophobic thermoplastic remain as an obstacle in natural fiber/thermoplastic biocomposites. Consequently, surface treatment of fiber is of important to impart adhesion. The present work used consecutive superheated steam-alkali treatment to treat the oil palm mesocarp fiber (OPMF) prior to biocomposite fabrication. The biocomposites made up of 70 wt% treated OPMF and 30 wt% poly (butylene succinate) (PBS) were prepared by melt blending technique in a Brabender internal mixer followed by hot-press moulding into 1 mm sheets. A silane coupling agent of (3-aminopropyl) trimethoxysilane (APTMS) was also added to the biocomposite during the process of compounding to promote interfacial adhesion and enhance the properties of biocomposites. The results showed that the biocomposite containing 2 wt% APTMS showed maximum enhancement in tensile strength (89%), tensile modulus (812%) and elongation at break (52%) in comparison to that of untreated OPMF/PBS biocomposite. The SEM observation of the tensile fracture surface revealed that APTMS improved the interfacial adhesion between treated OPMF and PBS. It can be deduced that the presence of APTMS can improve the adhesion between hydrophilic fiber and hydrophobic thermoplastic, and thus increased the tensile properties of the biocomposite

Preparation and characterization of polyhydroxybutyrate/polycaprolactone/Mg-Al layered double hydroxide nanocomposites

Anionic clay Mg-Al Layered double hydroxide (Mg-Al LDHs) of Mg/Al-NO3 - with M2+:M3+ (3:1) ratio was synthesized by co-precipitation method from nitrate salt solutions were used with continuous agitation at constant pH 9. Beside, modification of nitrate anions by stearate anions between the LDH layers had carried out through ion exchange reaction. Polyhydroxybutyrate (PHB)/Polycaprolactone (PCL)/stearate Mg-Al Layered Double Hydroxide (LDH) nanocomposites were prepared via solution casting intercalation method. FT-IR spectra showed the presence of carboxylic acid (COOH) group indicates that stearate anions were successfully replacing the nitrate anions in the interlayer Mg-Al LDH. The XRD results showed that increasing basal spacing from 8.66 to 32.97 Å in modified stearate Mg-Al LDH. Additional of 1.0 wt % stearate Mg-Al LDH resulting higher basal spacing where polymer chain intercalated into interlayer LDH and TEM results revealed that the 1.0 wt % stearate Mg-Al LDH layers are homogeneously distributed in the PHB/PCL polymer blends matrix. TGA characterization proven that 80PHB/20PCL/1stearate Mg-Al LDH has lower weight loss and higher thermal stability. Enhancement in 300% elongation at break and 66% tensile strength in the presence of 1.0 wt % of the stearate Mg-Al LDH as compare with PHB/PCL blends. Scanning electron microscopy (SEM) proved that clay improves compatibility between polymer matrix and the best ratio 80PHB/20PCL/1stearate Mg-Al LDH surface was well dispersed and stretched before it breaks

Oil palm mesocarp fiber as new lignocellulosic material for fabrication of polymer/fiber biocomposites

New biocomposites consisting of poly (butylene succinate) (PBS) and various content (0-70 wt%) of oil palm mesocarp fiber (OPMF) or oil palm empty fruit bunch fiber (OPEFBF) were fabricated by melt blending and subsequently hotpress moulding. The tensile, flexural, and impact properties of those biocomposites were evaluated and compared. Enhancement of flexural modulus of 200 or 150% was observed with PBS biocomposite loaded with 70 wt% of OPMF or OPEFBF. PBS/OPMF biocomposites exhibited higher values of tensile, flexural and impact strengths, and tensile and flexural moduli than those of PBS/OPEFBF biocomposites. These results indicated that OPMF feature better reinforcing agent for PBS as compared to that of OPEFBF

Mechanical and morphological properties of sterate modified layered double hydroxide blend with polyhydroxybutyrate/poly(lactic acid) nanocomposites

In this study, poly(3-hydroxybutyrate) (PHB)/poly(lactic acid) (PLA)/stearate modified magnesium aluminum layered double hydroxides (SMALDH) nanocomposites were prepared from PHB/PLA blend and SMALDH by solvent-casting method. The ratio of PHB/PLA was fixed at 90/10 as it gave the optimum tensile properties among the blends. Mg/Al layered double hydroxide (MALDH) was first synthesized via a co-precipitation method from nitrates salt solution and then modified with sodium stearate via an anion exchange process. X-ray diffraction (XRD) result showed an incensement in d-spacing of MALDH from 7.88 to 30.26 Å after it was modified with sodium stearate, suggested that the intercalation of stearate ions into the interlayer of MALDH. The addition of 1.5 wt% of SMALDH improved the tensile strength and tensile modulus of PHB/PLA blend by 23% and 13%, respectively. Those improvements were attributed to the improved interfacial adhesion of blend components as illustrated in scanning electron micrograph. XRD result and transmission electron micrograph showed that the nanocomposites produced are of mixture intercalated/exfoliated types