Science Letters

Electrical and Mechanical Properties of Silicone Electrically Conductive Adhesive (ECAs) Filled Graphene-Carbon Black (GR-CB)

Muhammad Hanif Azhar — 2025-01-30

ECAs were successfully introduced to replace hazardous lead-based solder, but their electrical conductivity and mechanical properties are limited. Hence, the incorporation of carbon black (CB) and Graphene (GR) filled silicone based ECAs with various ratios of GR and CB (0:0, 1:0, 0:1, 10:5, 5:10, 5:5, and 3:5) via solvent casting technique was investigated. The characterization of the conductive adhesive film using Fourier Transform Infrared Spectroscopy (FTIR) and electrochemical impedance spectroscopy (EIS) was investigated using the Nyquist plot and conductivity of silicone film. Meanwhile, the mechanical properties were measured using tensile and hardness tests. The appearance of a sharp peak in the FTIR spectrum confirmed that the interaction between the silicone matrix and GR-CB occurred (Si-CH3). The optimum ratio with the highest conductivity value, 7.98 10-8 Ω cm-1, was obtained by the synergistic effect of conductive fillers, which is GR with CB at 10:5 GR-CB ratio, which might be attributed to the synergistic effect from the filler. At the same time, tensile and hardness tests on silicone ECA samples exhibited that the optimum ratio of synergistic GR-CB was at 5:10 with the highest tensile strength, young modulus, elongation at break, and hardness with values of 1.16 MPa, 2.02 MPa, 25.64 mm, and 47.56, respectively due to the inherent stiffness of CB and GR. Finally, the electrical and mechanical properties revealed that adding GR and CB improved the conductivity, strength, and toughness of silicone ECAs composites, making way for electronic applications.

Transformative Approaches to Produce PHAs from Waste Streams: A Brief Review

Norazlina Hashim — 2025-01-30

Throughout their existence, plastics made from petroleum have been
associated with increasing environmental problems, such as pollution,
accumulation in terrestrial and marine environments, and the release of
greenhouse gases. To address the present environmental concerns,
creating and producing eco-friendly polymers has received much
attention in the industrial and research communities over the past ten
years. The current review focuses on one of the beneficial products
obtained after the waste treatment. The biodegradable polymer,
Polyhydroxyalkanoates (PHAs), is synthesized from the variable
organic materials collected during the waste aerobic and anaerobic
treatment. PHAs with short-chain-length (scl-PHA) and medium-chain-
length (mcl-PHA) are commonly synthesized with different bacterial
strains as a factor to determine the chain length. Researchers studied
various methods to find the optimum parameters and yield of PHAs
while considering the cost. It can be concluded that pH 7 and 60 oC are
the optimum conditions for bacteria pretreatment to obtain a high
conversion of PHAs.
Furthermore, one of the potential wastes, Palm Oil Mill Effluent
(POME) obtained from palm oil production, was highlighted since
Malaysia is the world's second-largest palm oil industrial player. The
abundance of POME becomes highly toxic effluent and causes water
pollution. Hence, POME can be manipulated to play an important role
as one of the feedstocks for PHAs. This renewable PHAs biopolymer
can solve the plastic degradation and the pollution caused by
conventional polymers. The continuing improvement of PHAs was
extensively examined to fulfill the world PHAs market demand.

Synthesis and Characterization of Green Thermoplastic Composite from Renewable Resources

Auwal, A.S — 2025-01-30

Due to concerns regarding poor degradability and the potential
for environmental contamination, the utilization of
petrochemical-based plastics should be actively discouraged,
leading to a shift toward the adoption of biobased plastics derived
from natural sources. Biobased plastics, sourced from renewable
materials, are characterized by their elevated costs,
biodegradability, compostability, non-toxicity, and minimal
environmental impact. This study investigates the potential of
utilizing potato waste starch in the production of bioplastics
specifically for packaging applications. In this research, the
polymer matrix derived from potato waste was modified with
chitosan to enhance its antimicrobial, antifungal, and antiviral
properties. Such modifications are expected to significantly
improve the biocompatibility, bioadhesiveness, and non-toxicity
of the potato waste polymer. Consequently, a modified polymer
matrix known as chitosan-modified polylactic acid plastics was
synthesized. To further augment the mechanical properties of
these bioplastics, a jute fiber reinforcement was incorporated into
the polymer matrix.The characterization of the bioplastics was
conducted using Fourier-transformed infrared spectroscopy
(FTIR), while the tensile properties of the plastic composites
were evaluated through tensile testing procedures. The findings
indicated that the tensile strength of the composites exhibited an
increase in correlation with the concentration of the modifier.
Conversely, a significant reduction in elongation at break was
observed as the concentration of the modifier increased,
highlighting the trade-off between strength and flexibility in the
modified bioplastics.