scholarly journals Heat Properties of Polylactic Acid Biocomposites after Addition of Plasticizers and Oil Palm Frond Microfiber

2020 ◽  
Vol 23 (8) ◽  
pp. 295-304
Author(s):  
Wida Banar Kusumaningrum ◽  
Firda Aulya Syamani ◽  
Lisman Suryanegara

Polylactic acid (PLA) is a biopolymer that can replace thermoplastic polymers such as polypropylene (PP) in various applications due to strength, young modulus, biocompatibility, biodegradability, good clarity, oil resistance, and oxygen barrier ability. However, PLA has some drawbacks, including brittle, high glass transition temperature (Tg), and low degradation and crystallization rates. Therefore, modification is needed with the addition of nucleating agents and plasticizers to overcome these limitations of PLA. This research aims to study the effect of plasticizers and microfibril cellulose of oil palm frond (OPF) on thermal stability and to review the crystallization kinetics of PLA biocomposites. Polyethylene glycol and triacetin were used as plasticizers. Thermal analysis was performed using Thermal Gravimetry analysis (TGA) and Differential Scanning Calorimetry (DSC). The crystallization kinetics study was analyzed using a modified Avrami model under non-isothermal conditions. PLAP4000 has better thermal stability than PLAP200 and PLAG with Tonset and Tmax values reaching 349.17°C and 374.68°C, respectively, which are close to pure PLA. All types of plasticizers influenced decreasing the Tg value in the range of 27–42%, whereas OPF microfiber addition contributes to a Tg reduction of 37-55 %. Crystallization kinetic study was informed for heterogeneous and simultaneous nucleation mechanisms with an n value range of about 2-3 for PLAP4000 and PLAOP4000. The crystallization rate was multiplied 4-9-fold for PLAOP200 and 2-3-fold for PLAOP4000.

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3226
Author(s):  
Siti Shazra Shazleen ◽  
Lawrence Yee Foong Ng ◽  
Nor Azowa Ibrahim ◽  
Mohd Ali Hassan ◽  
Hidayah Ariffin

This work investigated the combined effects of CNF nucleation (3 wt.%) and PLA-g-MA compatibilization at different loadings (1–4 wt.%) on the crystallization kinetics and mechanical properties of polylactic acid (PLA). A crystallization kinetics study was done through isothermal and non-isothermal crystallization kinetics using differential scanning calorimetry (DSC) analysis. It was shown that PLA-g-MA had some effect on nucleation as exhibited by the value of crystallization half time and crystallization rate of the PLA/PLA-g-MA, which were increased by 180% and 172%, respectively, as compared to neat PLA when isothermally melt crystallized at 100 °C. Nevertheless, the presence of PLA-g-MA in PLA/PLA-g-MA/CNF3 nanocomposites did not improve the crystallization rate compared to that of uncompatibilized PLA/CNF3. Tensile strength was reduced with the increased amount of PLA-g-MA. Contrarily, Young’s modulus values showed drastic increment compared to the neat PLA, showing that the addition of the PLA-g-MA contributed to the rigidity of the PLA nanocomposites. Overall, it can be concluded that PLA/CNF nanocomposite has good performance, whereby the addition of PLA-g-MA in PLA/CNF may not be necessary for improving both the crystallization kinetics and tensile strength. The addition of PLA-g-MA may be needed to produce rigid nanocomposites; nevertheless, in this case, the crystallization rate of the material needs to be compromised.


Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 376
Author(s):  
Su-Mei Huang ◽  
Jiunn-Jer Hwang ◽  
Hsin-Jiant Liu ◽  
An-Miao Zheng

In this study, the montmorillonite (MMT) clay was modified with NH4Cl, and then the structures were exfoliated or intercalated in a polylactic acid (PLA) matrix by a torque rheometer in the ratio of 0.5, 3.0, 5.0 and 8.0 wt%. X-ray diffraction (XRD) revealed that the organic modified-MMT(OMMT) was distributed successfully in the PLA matrix. After thermal pressing, the thermal stability of the mixed composites was measured by a TGA. The mixed composites were also blended with OMMT by a co-rotating twin screw extruder palletizing system, and then injected for the ASTM-D638 standard specimen by an injection machine for measuring the material strength by MTS. The experimental results showed that the mixture of organophilic clay and PLA would enhance the thermal stability. In the PLA mixed with 3 wt% OMMT nanocomposite, the TGA maximum decomposition temperature (Tmax) rose from 336.84 °C to 339.08 °C. In the PLA mixed with 5 wt% OMMT nanocomposite, the loss of temperature rose from 325.14 °C to 326.48 °C. In addition, the elongation rate increased from 4.46% to 10.19% with the maximum loading of 58 MPa. After the vibrating hydrolysis process, the PLA/OMMT nanocomposite was degraded through the measurement of differential scanning calorimetry (DSC) and its Tg, Tc, and Tm1 declined.


Author(s):  
F S Hashim ◽  
H W Yussof ◽  
M A K M Zahari ◽  
R A Rahman ◽  
R M Illias

2014 ◽  
Vol 893 ◽  
pp. 488-491 ◽  
Author(s):  
Elfarizanis Baharudin ◽  
Alyani Ismail ◽  
Adam Reda Hasan Alhawari ◽  
Edi Syams Zainudin ◽  
Dayang L.A. Majid ◽  
...  

This paper presents the results on dielectric properties of pulverized material based on agricultural waste namely oil palm frond and pineapple leaf fiber for microwave absorber application in the X-band frequency range. The investigation is started by identifying the pulverized materials permittivities and loss tangents using coaxial probe technique, followed by density measurement comprising the determination of bulk and solid densities. Then, by using dielectric mixture model, the solid particle dielectric properties were determined. It is observed that the air properties give quite an effect on the permittivity and loss tangent of the pulverized materials. It is also found that the lower the material density the higher material dielectric constant will be. Furthermore, the results show that, both oil palm frond and pineapple leaf fiber are potential to be X-band absorber with average dielectric constant of 4.40 and 3.38 respectively. The loss tangents for both materials were observed to be more than 0.1 which mark them as lossy materials.


Author(s):  
Siti Nur Ridhwah Muhamed Ramli ◽  
Tengku Elida Tengku Zainal Mulok ◽  
Sabiha Hanim Mohd Salleh ◽  
Khalilah Abdul Khalil ◽  
Othman Ahmad ◽  
...  

2020 ◽  
Vol 21 (5) ◽  
Author(s):  
Roni Pazla ◽  
Novirman Jamarun ◽  
Fauzia Agustin ◽  
Mardiati Zain ◽  
Arief Arief ◽  
...  

Abstract. Pazla R, Jamarun N, Agustin F, Zain M, Cahyani NO. 2020. Effects of supplementation with phosphorus, calcium and manganese during oil palm frond fermentation by Phanerochaete chrysosporium on ligninase enzyme activity. Biodiversitas 21: 1833-1838. The objective of this study was to evaluate the effects of supplementation with phosphorus (P) in combination with calcium (Ca) and manganese (Mn) during oil palm frond (OPF) fermentation by Phanerochaete chrysosporium on ligninase enzyme activity and lignin degradation. This study was carried out using a randomized complete design with 3 treatments (addition of P, Ca and Mn) and 5 replicates. The following treatments were performed: T1 (P 1000 + Ca 2000 + Mn 150 ppm), T2 (P 1500 + Ca 2000 + Mn 150 ppm), and T3  (P 2000 + Ca 2000 +Mn 150 ppm). The data were subjected to an analysis of variance (ANOVA), and differences between treatment means were tested using Duncan's multiple range test (DMRT). The parameters measured were as follows: lignin peroxidase (LiP) activity (U/mL), manganese peroxidase (MnP) activity (U/mL), crude protein (CP) content (%), crude fiber (CF) content (%) and the decrease in lignin (%). The results revealed a significant increase in LiP activity and CP content and a decrease in the lignin content (p<0.05) by the addition of P in the T3 treatment. However, the treatment nonsignificantly increased (p>0.05) MnP activity and significantly decreased (P<0.05) the CF content. In conclusion, supplementation of the OPF fermentation process with P 2000, Ca 2000, and Mn 150 ppm resulted in the highest ligninase enzyme activity and in decreased lignin content.


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