The effect of silk fibroin nanoparticles on the morphology, rheology, dynamic mechanical properties, and toughness of poly(lactic acid)/poly(ε‐caprolactone) nanocomposite

2020 ◽  
Vol 137 (40) ◽  
pp. 49232 ◽  
Author(s):  
Masoud Dadras Chomachayi ◽  
Azam Jalali‐arani ◽  
Joaquín Martínez Urreaga
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Silk Fibroin ◽  
Dynamic Mechanical Properties ◽  
Poly Lactic Acid ◽  
Dynamic Mechanical ◽  
Silk Fibroin Nanoparticles

Morphology, thermal and dynamic mechanical properties of poly(lactic acid)/expandable graphite (PLA/EG) flame retardant composites

2017 ◽  
Vol 32 (1) ◽  
pp. 89-107 ◽  
Author(s):  
Mfiso Emmanuel Mngomezulu ◽  
Adriaan Stephanus Luyt ◽  
Maya Jacob John
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Glass Transition ◽  
Flame Retardant ◽  
Dynamic Mechanical Properties ◽  
Poly Lactic Acid ◽  
Expandable Graphite ◽  
Damping Factor ◽  
Melt Mixing ◽  
Dynamic Mechanical

This work reports on the effect of expandable graphite (EG) on the morphology, thermal and dynamic mechanical properties of flame retardant poly(lactic acid) (PLA)/EG composites. The composites were prepared by melt-mixing and their structure, morphology, melting and crystallization behaviour, as well as their dynamic mechanical properties, were investigated. It was found that graphite layers still existed in an aggregate structure with poor filler dispersion resulting in a lack of interfacial adhesion between EG and the PLA matrix. The presence of EG did not favour the crystallization of PLA, increased the glass transition temperature and showed a reduction in the crystallinity of the composites. The composites with higher filler contents showed enhanced storage and loss moduli. The glass transition temperatures from the loss modulus and damping factor curves varied inconsistently with EG content. The use of commercial EG as filler in PLA can preserve the thermal properties of injection moulding grade Cereplast PLA.

Investigations on jute fibre-reinforced polyester composites: Effect of alkali treatment and poly(lactic acid) coating

2018 ◽  
Vol 49 (7) ◽  
pp. 923-942 ◽  
Author(s):  
MK Gupta
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Loss Modulus ◽  
Alkali Treatment ◽  
Dynamic Mechanical Properties ◽  
Poly Lactic Acid ◽  
Jute Fibre ◽  
Static Compression ◽  
Dynamic Mechanical ◽  
Polyester Composites

The aim of the present investigation is to overcome the limitations of jute fibre-reinforced polyester composite. The jute fibre-reinforced polyester composites were prepared by hand lay-up technique followed by static compression using constant fibres length 15 mm and constant fibres loading 16 wt.%. In the present work, treated jute fibres consisted of alkali treated, poly(lactic acid)-coated and alkali-treated coated with poly(lactic acid). Mechanical properties in terms of tensile, flexural and impact test, and dynamic mechanical properties in terms of storage modulus [Formula: see text], loss modulus [Formula: see text], damping [Formula: see text] and glass transition temperature [Formula: see text]of prepared composites were studied. In addition, water absorption properties in terms of percentage of water uptake and sorption, diffusion and permeability coefficient were also studied. In addition, morphological analysis of untreated and treated jute fibres and its polyester based composites was also carried out using scanning electron microscope. The results suggested that the limitations of jute fibre-reinforced polyester composites were significantly reduced after the treatment of fibres. The composite with alkali-treated jute fibres coated with poly(lactic acid) exhibited the best performance in terms of improvement in mechanical, dynamic mechanical and water resistance properties. The results obtained from present study show a successful attempt of a novel treatment.

Functionalized Cellulose Nanocrystals for Improving the Mechanical Properties of Poly(Lactic Acid)

2018 ◽  
Author(s):  
Jamileh Shojaeiarani ◽  
Dilpreet Bajwa
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Cellulose Nanocrystals ◽  
Mechanical Test ◽  
Poly Lactic Acid ◽  
Injection Molding Process ◽  
Molding Process ◽  
Dynamic Mechanical ◽  
Uniform Dispersion ◽  
The Impact

Biopolymers are emerging materials with numerous capabilities of minimizing the environmental hazards caused by synthetic materials. The competitive mechanical properties of bio-based poly(lactic acid) (PLA) reinforced with cellulose nanocrystals (CNCs) have attracted a huge interest in improving the mechanical properties of the corresponding nanocomposites. To obtain optimal properties of PLA-CNC nanocomposites, the compatibility between PLA and CNCs needs to be improved through uniform dispersion of CNCs into PLA. The application of chemical surface functionalization technique is an essential step to improve the interaction between hydrophobic PLA and hydrophilic CNCs. In this study, a combination of a time-efficient esterification technique and masterbatch approach was used to improve the CNCs dispersibility in PLA. Nanocomposites reinforced by 1, 3, and 5 wt% functionalized CNCs were prepared using twin screw extrusion followed by injection molding process. The mechanical and dynamic mechanical properties of pure PLA and nanocomposites were studied through tensile, impact and dynamic mechanical analysis. The impact fractured surfaces were characterized using scanning electron microscopy. The mechanical test results exhibited that tensile strength and modulus of elasticity of nanocomposites improved by 70% and 11% upon addition of functionalized CNCs into pure PLA. The elongation at break and impact strength of nanocomposites exhibited 43% and 35% increase as compared to pure PLA. The rough and irregular fracture surface in nanocomposites confirmed the higher ductility in PLA nanocomposites as compared to pure PLA. The incorporation of functionalized CNCs into PLA resulted in an increase in storage modulus and a decrease in tan δ intensity which was more profound in nanocomposites reinforced with 3 wt% functionalized CNCs.

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