Mechanical and moisture barrier properties of titanium dioxide nanoparticles and halloysite nanotubes reinforced polylactic acid (PLA)

Abstract

Abstract. Polylactic acid (PLA) has been larger used in biomedical field due to its low toxicity and biodegradability. The aim of this study was to produce PLLA nanocomposites, by melt extrusion, containing Halloysite nanotubes (HNT) and/or titanium dioxide (TiO 2 ) nanoparticles. Immediately after drying, PLLA was mechanically homogenized with the nanofillers and then melt blended using a single screw extruder (L/D = 30) at a speed of 110 rpm, with three heating zones in which the following temperatures were maintained: 150, 150 and 160ºC (AX Plásticos model AX14 LD30). The film samples were obtained by compression molding in a press with a temperature profile of 235 ± 5ºC for 2.5 min, after pressing, films were cooled up to room temperature. The mechanical tests were performed according to ASTM D882-09 and the water vapor permeability (WVP) was measured according to ASTM E-96, in triplicate. The tensile properties indicated that the modulus was improved with increased TiO 2 content up to 1g/100g PLLA. The Young's modulus (YM) of the PLA was increased from 3047 MPa to 3222 MPa with the addition of 1g TiO 2 /100g PLLA. The tensile strength (TS) of films increases with the TiO 2 content. In both cases, the YM and TS are achieved at the 1% content of TiO 2 and is due to the reinforcing effect of nanoparticles. Pristine PLA showed a strain at break (SB) of 3.56%, while the SB of nanocomposites were significant lower, for instance the SB of composite containing 7.5 g HNT/100g PLLA was around 1.90 %. The WVP of samples was increased by increasing the nano filler content. It should be expected that an increase of nanofiller content would decrease the mass transfer of water molecules throughout the samples due to the increase in the way water molecules will have to cross to permeate the material. However, this was not observed. Therefore, this result can be explained considering the molecular structure of both fillers, which contain several hydroxyl groups in the surface, making the end material more hydrophilic.

Poly Lactic Acid (PLA) Nanocomposites: Effect of Inorganic Nanoparticles Reinforcement on Its Performance and Food Packaging Applications

“…The silane treatment was effective in decreasing the WVTR at a lower concentration of ZnO NP impregnation due to the uniform distribution of NPs in the PLA matrix [ 43 ]. Clays can also provide gas and water vapour resistance and increase the biopolymer’s mechanical strength [ 58 ]. The reinforcement of TiO 2 and HNT NPs revealed a unique trend parallel to a greater hydroxyl groups on the surface of the NPs, enhancing the mass transfer of water molecules through the matrix, thereby increasing the WVTR.…”

Cellulose nanofibrils and nano-scaled titanium dioxide-reinforced biopolymer nanocomposites: Selecting the best nanocomposites with multicriteria decision-making methods

“…The addition of CNFs into the PLA matrix was found to significantly increase the mechanical properties of the BNs. 15 The previous studies showed that the addition of both the CNFs and nano-TiO 2 generally increased the mechanical properties of the PLA and PHB composites. 8,16,43,44 As a result, it can be said that the addition of the fillers had a positive effect on the mechanical properties of each biopolymer.…”

“…In another study on PLA and TiO 2 , Buzarovska and Grozdanov 14 found that adding TiO 2 to PLA had no significant influence on the characteristic temperatures such as T g , T c , and T m ; however, it increased the crystallinity of the composites. In another study, Alberton et al 15 found an increase in the mechanical properties of the PLA composites in the presence of the TiO 2 . In blends of PHB and CNFs, the obtained results showed that the addition of CNFs generally increased the mechanical properties of the PHB composites as compared with neat PHB; in addition, El-Hadi 12 found that adding CNFs improved the thermal properties of neat PHB.…”

“…WASPAS scores and ranking. Q ð1Þ i and Q ð2Þ i , the relative total importance of WSM and WPM based i alternatives, were calculated by using equations (14) and (15); further, the criteria shown in Table 8 were normalized with equation (12) or (13); then, the weighted general criteria values (Q i ) of the WSM and WPM method were determined. The k (total relative importance of alternatives) effect was calculated to determine the accuracy and effectiveness of the decision-making process.…”

Review of Recent Advances in Polylactic Acid/TiO2 Composites

“…Several research groups have reported an enhancement in mechanical performance of PLA with the incorporation of TiO 2 nanoparticles. Mechanical properties namely tensile strength (TS), Young’s modulus (YM), and elongation at break (EB) of PLA/TiO 2 composites fabricated via melt mixing technique were examined by Alberton et al [23]. While the values of TS and YM of the PLA were increased from ~53.66 MPa and ~3048 MPa into 58.28 MPa and 3237 MPa, respectively upon the incorporation of 1 wt.% TiO 2 owing to the reinforcing effect of TiO 2 nanoparticles, the EB value of PLA was found to be reduced from 3.56% to 3.00% with inclusion of 1 wt.% TiO 2 .…”