Synergistic effects of bio‐plasticizer and core–shell rubber on poly(lactic acid) toughness for sustainable flexible packaging applications

2021 ◽  
pp. 51894
Author(s):  
Nawadon Petchwattana ◽  
Benjatham Sukkaneewat ◽  
Phisut Naknaen ◽  
Jakkid Sanetuntikul ◽  
Ektinai Jansri
Polymers ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 796 ◽  
Author(s):  
Le Yang ◽  
Zaijun Yang ◽  
Feng Zhang ◽  
Lijin Xie ◽  
Zhu Luo ◽  
...  

Long chain branched poly (lactic acid) (LCBPLA) was prepared via transesterification between high molecular weight poly (lactic acid) (PLA) and low molar mass monomer trimethylolpropane triacrylate (TMPTA) during melt blending in the presence of zinc oxide nanoparticles (nano-ZnO) as a transesterification accelerant in a torque rheometer. Compared with the traditional processing methods, this novel way is high-efficiency, environmentally friendly, and gel-free. The results revealed that chain restructuring reactions occurred and TMPTA was grafted onto the PLA backbone. The topological structures of LCBPLA were verified and investigated in detail. It was found that the concentration of the accelerants and the sampling occasion had very important roles in the occurrence of branching structures. When the nano-ZnO dosage was 0.4 phr and PLA was sampled at the time corresponding to the reaction peak in the torque curve, PLA exhibited a star-shaped topological structure with a high branching degree which could obviously affect the melt strength, extrusion foaming performances, and crystallization behaviors. Compared with pristine PLA, LCBPLA showed a higher melt strength, smaller cell diameter, and slower crystallization speed owing to the synergistic effects of nano-ZnO and the long chain branches introduced by the transesterification reaction in the system. However, severe degradation of the LCBPLAs would take place under a mixing time that was too long and lots of short linear chains generated due to the excessive transesterification reaction, with a sharp decline in melt strength.


2019 ◽  
pp. 089270571986827 ◽  
Author(s):  
Mehrnoush Monshizadeh ◽  
Sajad Seifi ◽  
Iman Hejazi ◽  
Javad Seyfi ◽  
Hossein Ali Khonakdar

Synergistic effects of organo-modified Mg-Al layered double hydroxide (LDH) and triethyl citrate (TEC) on the properties of poly(lactic acid) (PLA) were demonstrated. PLA/LDH nanocomposites in the absence and presence of TEC were fabricated via solution casting technique. Morphological analysis revealed that as the LDH concentration increases, the number of aggregations is also increased; however, introduction of TEC considerably enhanced the dispersion quality of LDHs. Differential scanning calorimetry results showed that the addition of LDH and TEC had no significant influence on the crystallinity of nanocomposites obtained from solution casting. In contrast, once the samples were cooled from melt, the concurrent use of LDH and TEC led to a dramatic enhancement in the crystallinity of PLA ( X c = 55.5%). Moreover, the LDH nanoparticles counterbalanced the adverse effects of plasticization by TEC leading to enhanced toughness of the final nanocomposites. LDH had also a positive influence on thermal stability of PLA, indicating the heat-insulating role of LDH particles. In conclusion, the concurrent use of LDH and TEC could extend the applicability of PLA especially in food packaging applications.


2018 ◽  
Vol 98 ◽  
pp. 483-491 ◽  
Author(s):  
Hamad F. Alharbi ◽  
Monis Luqman ◽  
Khalil Abdelrazek Khalil ◽  
Yasser A. Elnakady ◽  
Omar H. Abd-Elkader ◽  
...  

Langmuir ◽  
2006 ◽  
Vol 22 (6) ◽  
pp. 2816-2821 ◽  
Author(s):  
Salvador A. Gómez-Lopera ◽  
José L. Arias ◽  
Visitación Gallardo ◽  
Ángel V. Delgado

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Sungho Lee ◽  
Tatsuya Miyajima ◽  
Ayae Sugawara-Narutaki ◽  
Katsuya Kato ◽  
Fukue Nagata

Biodegradable nanoparticles have been well studied as biocompatible delivery systems. Nanoparticles of less than 200 nm in size can facilitate the passive targeting of drugs to tumour tissues and their accumulation therein via the enhanced permeability and retention (EPR) effect. Recent studies have focused on stimuli-responsive drug delivery systems (DDS) for improving the effectiveness of chemotherapy; for example, pH-sensitive DDS depend on the weakly acidic and neutral extracellular pH of tumour and normal tissues, respectively. In our previous work, core–shell nanoparticles composed of the biodegradable polymer poly(lactic acid) (PLA) and the widely used inorganic biomaterial hydroxyapatite (HAp, which exhibits pH sensitivity) were prepared using a surfactant-free method. These PLA/HAp core–shell nanoparticles could load 750 wt% of a hydrophobic model drug. In this work, the properties of the PLA/HAp core–shell nanoparticles loaded with the anti-cancer drug paclitaxel (PTX) were thoroughly investigated in vitro . Because the PTX-containing nanoparticles were approximately 80 nm in size, they can be expected to facilitate efficient drug delivery via the EPR effect. The core–shell nanoparticles were cytotoxic towards cancer cells (4T1). This was due to the pH sensitivity of the HAp shell, which is stable in neutral conditions and dissolves in acidic conditions. The cytotoxic activity of the PTX-loaded nanoparticles was sustained for up to 48 h, which was suitable for tumour growth inhibition. These results suggest that the core–shell nanoparticles can be suitable drug carriers for various water-insoluble drugs.


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