Preparation And Characterization Of Poly(Butylene Succinate)/ Poly(Butylene Adipate-Coterephthalate) Organo-Clay Nanocomposites

The present research aims at studying the influence of organoclay on the properties of poly(butylene succinate)/poly(butylene adipate-co-terephthalate), PBS/PBAT blend. The organoclay was modified via cation exchange method using organic surfactants; protonated octadecylamine (ODA), cetyltrimethylammonium (CTA) and dimethyldioctadecylammonium (DDOA). The characterizations of organoclays were carried out by the Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Thermogravimetric analysis (TGA). XRD and FTIR results indicated sodium montmorillonite (Na-MMT) was successfully modified to be organoclay through cation exchange method. XRD showed that the basal spacing of clay increased with the formation of organoclays. The PBS/PBAT blends were successfully prepared by melt blending technique. FTIR spectra revealed that the blends involved only physical interaction. Tensile strength and modulus decreased as the PBAT contents increased. SEM of the PBS/PBAT clearly demonstrated a two-phase morphology, which indicated the immiscibility of the components. The PBS/PBAT nanocomposites were prepared by melt intercalation technique. The expansion of the basal spacing of the clay indicated the formation of intercalated as well as exfoliated types of nanocomposites which supported by XRD diffractograms and TEM images. FTIR spectra showed that there is strong interaction between clay and PBS/PBAT polymer matrix which gives rise to improvement in tensile properties. Tensile modulus increased with clay loading up to 7 wt% while improvements in tensile strength were limited. Tensile strength increased up to 1 wt% of clay while elongation at break decreased with the addition of clay. The thermogravimetric analysis showed the presence of clays give significant improvement in thermal stability, particularly organoclay. The DMA analysis showed an increase in the storage modulus and loss modulus with the addition of organoclay into PBS/PBAT blend compared with neat PBS/PBAT. Furthermore, the presence of organoclay influenced the morphology of the PBS/PBAT blend which showed more homogeneous and single phase morphology. This revealed that the organoclay acts as compatibilizer for the immiscible PBS/PBAT polymer blend. Biodegradability results indicated that nanocomposites exhibit the same or a higher level of biodegradability compared with the PBS/PBAT blend

Effect of organo-modified montmorillonite on poly(butylene succinate)/poly(butylene adipate-co-terephthalate) nanocomposites

The composite material based on poly(butylene succinate) (PBS), poly(butylene adipate-co-terephthalate) (PBAT) and organo-modified montmorillonite (OMMT) were prepared by melt blending technique and characterized. Sodium montmorillonite (Na-MMT) was successfully modified by octadecylammonium (ODA) and dimethyldioctadecylammonium (DDOA) salts to become OMMT through cation exchange technique which is shown by the increase of basal spacing of clay by XRD. The addition of the OMMT to the PBS/PBAT blends produced nanocomposites which is proved by XRD and TEM. Tensile tests showed increase in tensile strength and modulus which is attributed to the existence of strong interactions between PBS/PBAT and clay, particularly with OMMT. Highest tensile strength of nanocomposite was observed at 1 wt% of OMMT incorporated. TGA study showed that the thermal stability of the blend increased after the addition of clays. SEM micrographs of the fracture surfaces show that the morphology of the blend becomes homogeneous and smoother with presence of OMMT

Morphology, thermal and mechanical properties of biodegradable poly(butylene succinate)/poly(butylene adipate-co-terephthalate)/clay nanocomposites

Sodium montmorillonite (Na-MMT) was successfully modified by octadecylamine (ODA) through a cation exchange technique that showed by the increased of basal spacing of clay by XRD. The addition of the organoclay into the PBS/PBAT blends produced intercalated-type nanocomposites with improvements in tensile modulus and strength. The highest tensile strength of nanocomposite was observed at 1 wt% of organoclay incorporated. A TGA study showed that the thermal stability of the blend increased after the addition of the organoclay by 1 wt%. SEM micrographs of the fracture surfaces show that the morphology of the blend becomes smoother with presence of organoclay

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

In vitro antimicrobial activity of green synthesized silver nanoparticles against selected gram-negative foodborne pathogens

Silver nanoparticles (AgNPs) used in this study were synthesized using pu-erh tea leaves extract with particle size of 4.06 nm. The antibacterial activity of green synthesized AgNPs against a diverse range of Gram-negative foodborne pathogens was determined using disk diffusion method, resazurin microtitre-plate assay (minimum inhibitory concentration, MIC), and minimum bactericidal concentration test (MBC). The MIC and MBC of AgNPs against Escherichia coli, Klebsiella pneumoniae, Salmonella Typhimurium, and Salmonella Enteritidis were 7.8, 3.9, 3.9, 3.9 and 7.8, 3.9, 7.8, 3.9 μg/mL, respectively. Time-kill curves were used to evaluate the concentration between MIC and bactericidal activity of AgNPs at concentrations ranging from 0×MIC to 8×MIC. The killing activity of AgNPs was fast acting against all the Gram-negative bacteria tested; the reduction in the number of CFU mL-1 was >3 Log10 units (99.9%) in 1-2 h. This study indicates that AgNPs exhibit a strong antimicrobial activity and thus might be developed as a new type of antimicrobial agents for the treatment of bacterial infection including multidrug resistant bacterial infection

Transparent blend of poly (Methylmethacrylate) / cellulose acetate butyrate for the protection from ultraviolet

The use of transparent polymers as an alternative to glass has become widespread. However,the direct exposure of these materials to climatic conditions of sunlight and heat decrease the lifetime cost of these products. The aim of this study was to minimize the harm caused by ultraviolet (UV) radiation exposure to transparent poly (methylmethacrylate)(PMMA), which usually leads to changes in the physical and chemical properties of these materials and reduced performance.This was achieved using Environmentally friendly cellulose acetate butyrate (CAB). The optical,morphological, and thermal properties of CAB blended with transparent PMMA was studied using UV-VIS spectrophotometry, scanning electron microscopy, X-ray diffraction, dynamic mechanical analysis, and thermal gravimetric analysis. The results show that CAB was able to reduce the effects of UV radiation by making PMMA more transparent to UV light, thereby preventing the negative effects of trapped radiation within the compositional structure, while maintaining the amorphous structure of the blend. The results also show that CAB blended with PMMA led to some properties commensurate with the requirements of research in terms of a slight increase in the value of the modulus and the glass transition temperature for the PMMA/CAB blend

Impact toughness and ductility enhancement of biodegradable poly(lactic acid)/poly(ε-caprolactone) blends via addition of glycidyl methacrylate

Poly(lactic acid) (PLA)/poly(ε-caprolactone) (PCL) blends were prepared via melt blending technique. Glycidyl methacrylate (GMA) was added as reactive compatibilizer to improve the interfacial adhesion between immiscible phases of PLA and PCL matrices. Tensile test revealed that optimum in elongation at break of approximately 327% achieved when GMA loading was up to 3wt%. Slight drop in tensile strength and tensile modulus at optimum ratio suggested that the blends were tuned to be deformable. Flexural studies showed slight drop in flexural strength and modulus when GMA wt% increases as a result of improved flexibility by finer dispersion of PCL in PLA matrix. Besides, incorporation of GMA in the blends remarkably improved the impact strength. Highest impact strength was achieved (160% compared to pure PLA/PCL blend) when GMA loading was up to 3 wt%. SEM analysis revealed improved interfacial adhesion between PLA/PCL blends in the presence of GMA. Finer dispersion and smooth surface of the specimens were noted as GMA loading increases, indicating that addition of GMA eventually improved the interfacial compatibility of the nonmiscible blend

Synthesis and characterisation of functionalised-graphene oxide by gamma-ray irradiation

Gamma-ray irradiation technique was used to functionalise graphene oxide (GO) with various alkyl chain length alkylamine. Functionalisation of alkylchain onto the GO was confirmed by nuclear magnetic resonance (1H NMR), Fourier transform infrared (FTIR) and X-ray diffraction (XRD). FTIR of functionalised GO showed the appearance of significant peaks around 2850–2960 cm–1 (–CH2) which come from long alkylchain together with peak around 1450–1560 cm–1 indicating the formation of C–NH–C. XRD showed an additional diffraction peak at lower 2θ angle, indicating that the intercalation of alkylamine was successful. The effects of various alkyl lengths functionalised-GO on morphological and thermal properties were investigated. Scanning electron microscopy (SEM) analysis showed an increase in surface roughness when the alkyl chain length increases. The addition of alkylchain on GO surfaces significantly improves the thermal stability of GO, suggesting their great potential for hydrophobic material in industry

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

The mechanical, thermal and morphological properties of graphene nanoplatelets filled poly(lactic acid)/epoxidized palm oil blends / Buong Woei Chieng ... [et al.]

Poly(lactic acid) (PLA)-based nanocomposites filled with graphene nanoplatelets (xGnP) that contains 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 properties. Plasticized and nanofilled PLA nanocomposites (PLA/EPO/xGnP) showed improvement in the elongation at break by 3322% and 61% compared to pristine PLA and PLA/EPO, respectively. 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. XRD pattern showed the presence of peak around 26.5° in PLA/EPO/xGnP nanocomposites which corresponds to characteristic peak of graphene nanoplatelets. Plasticized PLA reinforced with xGnP showed that increasing the xGnP content triggers a substantial increase in thermal stability. Crystallinity of the nanocomposites as well as cold crystallization and melting temperature did not show any significant changes upon addition of xGnP. However, there was a significant decrease of glass transition temperature up to 0.3wt% of xGnP incorporation. The TEM micrograph of PLA/EPO/xGnP shows that the xGnP was uniformly dispersed in the PLA matrix and no obvious aggregation was observed