Effect of Alumina Microparticle-Infused Polymer Matrix

Effect of Alumina #Microparticle-Infused #Polymer Matrix on Mechanical Performance of #Carbon #Fiber Reinforced Polymer (#CFRP) Composite

by Ganesh Radhakrishnan et al.

J. Compos. Sci. 2025, 9(7), 360; https://lnkd.in/ddh-RXhY

Abstract

In recent times, fiber reinforced polymer composite materials have become more popular due to their remarkable features such as high specific strength, high stiffness and durability. Particularly, Carbon Fiber Reinforced Polymer (CFRP) composites are one of the most prominent materials used in the field of transportation and building engineering, replacing conventional materials due to their attractive properties as mentioned. In this work, a CFRP laminate is fabricated with carbon fiber mats and epoxy by a hand layup technique. Alumina (Al₂O₃) micro particles are used as a filler material, mixed with epoxy at different weight fractions of 0% to 4% during the fabrication of CFRP laminates. The important objective of the study is to investigate the influence of alumina micro particles on the mechanical performance of the laminates through characterization for various physical and mechanical properties. It is revealed from the results of study that the mass density of the laminates steadily increased with the quantity of alumina micro particles added and subsequently, the porosity of the laminates is reduced significantly. The SEM micrograph confirmed the constituents of the laminate and uniform distribution of Al₂O₃ micro particles with no significant agglomeration. The hardness of the CFRP laminates increased significantly for about 60% with an increase in weight % of Al₂O₃ from 0% to 4%, whereas the water gain % gradually drops from 0 to 2%, after which a substantial rise is observed for 3 to 4%. The improved interlocking due to the addition of filler material reduced the voids in the interfaces and thereby resist the absorption of water and in turn reduced the plasticity of the resin too. Tensile, flexural and inter-laminar shear strengths of the CFRP laminate were improved appreciably with the addition of alumina particles through extended grain boundary and enhanced interfacial bonding between the fibers, epoxy and alumina particles, except at 1 and 3 wt.% of Al₂O₃, which may be due to the pooling of alumina particles within the matrix. Inclusion of hard alumina particles resulted in a significant drop in impact strength due to appreciable reduction in softness of the core region of the laminates.

source: Journal of Composites Science

#carbonfiber #composites #alumina #epoxy

Today's KNOWLEDGE Share : Tackifiers in Tire Manufacturing

Today's KNOWLEDGE Share

Tackifiers in Tire Manufacturing

* Tack is considered the ability of two uncured rubber compound surfaces to adhere together. Because most synthetic rubbers are less tacky than natural rubber, it is often necessary to add tackifying substances. These substances should give rubber compounds sufficient tack that is maintained during storage and facilitate processing, in order that the components of a green tire will hold together until the curing process and prevent tearing during molding in the curing press.

* Changes in environmental conditions can dictate adjustments to the tackifier level. For instance, in hot summer months, you might need to decrease the tackifier to prevent the compound from becoming too sticky. Conversely, in cold months, it might be necessary to increase the tackifier to ensure sufficient adhesion is maintained. Therefore, tack properties must be optimized to avoid possible defects due to unsuitable tack levels.

* Tackifying resins generally have a softening range of 80°C to 110°C and should be incorporated early in the mixing cycle (masterbatch) to ensure proper dispersion.

* One of the preferred tackifier resins in tire manufacturing is phenol resin. General tackifying resins form weak Van der Waals forces, through which tackiness forms, whereas phenolic resins form stronger hydrogen bonds with the rubber surface so with lower loading , the compound achieves sufficient tack.

source : Ahmed Awad

Today's KNOWLEDGE Share : Rice researchers develop superstrong, eco-friendly materials from bacteria

Today's KNOWLEDGE Share

Rice researchers develop superstrong, eco-friendly materials from bacteria

Scientists at Rice University and University of Houston have developed an innovative, scalable approach to engineer bacterial cellulose into high-strength, multifunctional materials. The study, published in Nature Communications, introduces a dynamic biosynthesis technique that aligns bacterial cellulose fibers in real-time, resulting in robust biopolymer sheets with exceptional mechanical properties.

Plastic pollution persists because traditional synthetic polymers degrade into microplastics, releasing harmful chemicals like bisphenol A (BPA), phthalates and carcinogens. Seeking sustainable alternatives, the research team led by Muhammad Maksud Rahman, assistant professor of mechanical and aerospace engineering at the University of Houston and adjunct assistant professor of materials science and nanoengineering at Rice, leveraged bacterial cellulose — one of Earth’s most abundant and pure biopolymers — as a biodegradable alternative.

“Our approach involved developing a rotational bioreactor that directs the movement of cellulose-producing bacteria, aligning their motion during growth,” said M.A.S.R. Saadi, the study’s first author and a doctoral student in material science and nanoengineering at Rice. “This alignment significantly enhances the mechanical properties of microbial cellulose, creating a material as strong as some metals and glasses yet flexible, foldable, transparent and environment friendly.”

Bacterial cellulose fibers usually form randomly, which limits their mechanical strength and functionality. By harnessing controlled fluid dynamics within their novel bioreactor, the researchers achieved in situ alignment of cellulose nanofibrils, creating sheets with tensile strength reaching up to 436 megapascals.

Moreover, incorporating boron nitride nanosheets during synthesis resulted in a hybrid material with even greater strength — around 553 megapascals — and improved thermal properties, demonstrating a heat dissipation rate three times faster than control samples.

“This dynamic biosynthesis approach enables the creation of stronger materials with greater functionality,” Saadi said. “The method allows for the easy integration of various nanoscale additives directly into the bacterial cellulose, making it possible to customize material properties for specific applications.

Shyam Bhakta, a postdoctoral fellow in the Department of BioSciences at Rice, played an important role in advancing the biological aspects of the study. Other Rice collaborators included Pulickel Ajayan, the Benjamin M. and Mary Greenwood Anderson Professor of Materials Science and NanoEngineering; Matthew Bennett, professor of biosciences; and Matteo Pasquali, the A.J. Hartsook Professor of Chemical and Biomolecular Engineering.

“The synthesis process is essentially like training a disciplined bacterial cohort,” Saadi explained. “Instead of having the bacteria move randomly, we instruct them to move in a specific direction, thus precisely aligning their cellulose production. This disciplined motion and the versatility of the biosynthesis technique allows us to simultaneously engineer both alignment and multifunctionality.”

The scalable, single-step process holds significant promise for numerous industrial applications, including structural materials, thermal management solutions, packaging, textiles, green electronics and energy storage systems.

“This work is a great example of interdisciplinary research at the intersection of materials science, biology and nanoengineering,” Rahman added. “We envision these strong, multifunctional and eco-friendly bacterial cellulose sheets becoming ubiquitous, replacing plastics in various industries and helping mitigate environmental damage.

The research was supported by the National Science Foundation (2234567), the U.S. Endowment for Forestry and Communities (23-JV−11111129-042) and the Welch Foundation (C-1668). The content herein is solely the responsibility of the authors and does not necessarily represent the official views of the funding organizations and institutions.

source: Rice University

video : https://www.youtube.com/watch?v=WRYi0ulIB7I

Today's KNOWLEDGE Share : Scientists use cellulose nanofibers to boost biodegradability and strength of bioplastics

Today's KNOWLEDGE Share

Scientists use cellulose nanofibers to boost biodegradability and strength of bioplastics

Society has long struggled with petroleum-derived plastic pollution, and awareness of microplastics’ detrimental effects on food and water supplies adds further pressure.

In response, researchers have been developing biodegradable versions of traditional plastics, or “bioplastics.” However, current bioplastics face challenges as well: Current versions are not as strong as petrochemical-based plastics, and they only degrade through a high-temperature composting system.

Researchers at Washington University in St. Louis, have solved both problems with inspiration from the humble leaf. Long before plastic, humans wrapped their food in leaves, which easily biodegrade due to an underlying structure of cellulose-rich cell walls. WashU’s chemical engineers decided to introduce cellulose nanofibers to the design of bioplastics.

Cellulose layer unlocks barrier properties for packaging

Technology emerged from working with two of the highest production bioplastics today. In a study published in Green Chemistry earlier this year, Yuan and colleagues used a variation of their leaf-inspired cellulose nanofiber structure to improve the strength and biodegradability of polyhydroxybutrate (PHB), a starch-derived plastic; they further refined their technique for polylactic acid (PLA), as detailed in a new paper just published in Nature Communications.

 

“We created this multilayer structure where cellulose is in the middle and the bioplastics are on two sides,” said Joshua Yuan, the Lucy and Stanley Lopata professor and chair of energy, environmental and chemical engineering at the McKelvey School of Engineering. Yuan is also director of the National Science Foundation-funded Carbon Utilization Redesign for Biomanufacturing (CURB) Engineering Research Center. “In this way, we created a material that is very strong and that offers multifunctionality,” he added.

 

The plastic packaging market is a $23.5 billion industry dominated by polyethylene and polypropylene; polymers made from petroleum that break down into harmful microplastics. The researchers’ optimized bioplastic, called Layered, Ecological, Advanced and multi-Functional Film (LEAFF), turned PLA into a packaging material that is biodegradable at room temperature. Additionally, the structure allows for other critical properties, such as low air or water permeability, helping keep food stable, and a surface that is printable. This improves bioplastics’ affordability since it saves manufacturers from printing separate labels for packaging. 

 

“On top of all of this, the LEAFF’s underlying cellulose structure gives it a higher tensile strength than even petrochemical plastics like polyethylene and polypropylene,” explained Puneet Dhatt, a PhD student in Yuan’s lab and first author on the article.

 

The innovation was in adding that cellulosic structure that WashU’s engineers replicated, cellulose fibrils embedded within the bioplastics.

 

“This unique biomimicking design allows us to address the limitations of bioplastic usage and overcome that technical barrier and allow for broader bioplastic utilization,” Yuan said.

Circular economy ready

The United States is uniquely positioned to dominate the bioplastics market and establish a ‘circular economy’ wherein waste products are reused, fed back into systems instead of left to pollute the air and water or sit in landfills.

 

Yuan hopes this technology can scale up soon and seeks commercial and philanthropic partners to help bring these improved processes to industry. Competitors from Asian and European research institutions also are working to develop similar technology. But U.S. industries have an advantage due to the country’s vast agriculture system — and WashU is near the center of the nation’s agrichemical industry.

 

“The U.S. is particularly strong in agriculture,” Yuan said. “We can provide the feedstock for bioplastic production at a lower price compared to other parts of the world.”

 

The feedstock Yuan is referring to are chemicals such as lactic acid, acetate or fatty acids like oleate, products of corn or starch fermentation by microbes that serve as bioplastic factories.

 

Pseudomonas putida, for instance, is a microbial strain widely used in the fermentation industry, including to produce a variety of polyhydroxyalkanoates (PHA), including PHB. McKelvey Engineering researchers have designed ways to convert various wastes, including carbon dioxide, lignin and food waste, into bioplastics using strains such as P. putida. With improved bioplastic design, Yuan’s research further fills in that loop, with a version of PHB and PLA that could be produced much more efficiently and degrade safely into the environment.

 

“The United States has a waste problem, and circular reuse could go a long way to turning that waste into useful materials,” Yuan said. “If we can ramp up our bioplastic supply chain, it would create jobs and new markets,” he said.

source: Washington University in St. Louis / SpecialChem

Today's KNOWLEDGE Share : EU Court of Justice upholds annulment of titanium dioxide carcinogen classification

Today's KNOWLEDGE Share

EU Court of Justice upholds annulment of titanium dioxide carcinogen classification

#Titaniumdioxide is used, inter alia, in the form of a white pigment, in various products, including paints, medicinal products, foodstuffs and toys.

In 2016, the Agence nationale de sécurité sanitaire de l’alimentation, de l’environnement et du travail (National Agency for Food, Environmental and Occupational Health and Safety (ANSES), France) submitted to the European Chemicals Agency (ECHA) a proposal for classification of titanium dioxide as a carcinogen by inhalation.

1 The following year, the ECHA Committee for Risk Assessment (RAC) adopted an opinion stating that the classification of that substance was justified.

2 On the basis of that opinion, in 2019, the European Commission adopted a regulation,

3 proceeding with the classification and labelling of titanium dioxide.

4 More specifically, according to the Commission, that substance was suspected of being carcinogenic to humans, by inhalation, in powder form containing 1% or more of particles of a diameter equal to or below 10 μm. Various manufacturers, importers, downstream users and suppliers of titanium dioxide challenged that classification and labelling before the General Court of the European Union. By judgment of 23 November 2022,

5 the General Court annulled the contested classification and labelling. It found, in particular,

6 that the Commission had committed a manifest error in its assessment of the acceptability and reliability of a scientific study on which the classification had been based. France and the Commission appealed to the Court of Justice against that judgment of the General Court.

By today’s judgment, the Court of Justice dismisses those appeals and thus upholds the judgment of the General Court and the annulment of the contested classification of titanium dioxide as a carcinogen. According to the Court of Justice, even though the General Court exceeded the limits of its judicial review,

7 the annulment of the contested classification and labelling is nevertheless justified. The General Court was fully entitled to hold that the RAC had failed to take into account all the relevant factors for the purposes of assessing the scientific study in question. 

source: Court of Justice of European Union

Kaynes Technology Subsidiary to Invest ₹4,995 Crore (~570 millions USD) in Tamil Nadu

Kaynes Circuits India Pvt Ltd, a subsidiary of #KaynesTechnology, has signed a non-binding Memorandum of Understanding (MoU) with the #TamilNadu government. As per the filing, the agreement was signed on August 4, 2025, and mentions an investment of ₹4,995 crore over the next 6 years for setting up new manufacturing facilities in the state.

It will include greenfield projects and expansion of existing capacities. The company has not yet shared specific timelines for the start of construction or production.

Range of Products to Be Manufactured

The unit will focus on manufacturing advanced #electronics components. These include multilayer #PCBs (up to 74 layers), HDI PCBs, flexible PCBs, camera module assemblies, wire harnesses, and #highfrequencylaminates. These products are used in sectors like telecom, defence, aerospace, and consumer electronics.

The state’s investment promotion agency, Guidance, is expected to assist with infrastructure, clearances, and eligibility for financial incentives. The MoU allows for discussions on industrial policies, subsidies, and support packages, but no legal commitment has been made yet.

Employment and Ecosystem 

The facility in #Thoothukudi is expected to generate approximately 4,700 jobs and nearby districts. The location is close to the upcoming VinFast EV plant, which could support the development of a broader manufacturing cluster in the region.

source: AngelOne/ Kaynes Technology

SEKISUI CHEMICAL Achieves Progress in Creating PFAS-Free Pipes for Ultrapure Process Applications in the Manufacturing of Advanced Semiconductors

SEKISUI CHEMICAL CO., LTD. announced that, in response to the global trend of tighter regulations regarding perfluoroalkyl and polyfluoroalkyl substances (PFAS) and growing demand for reducing environmental impact, the Urban Infrastructure & Environmental Products Company had been developing a new technology for PFAS-free pipe materials for ultrapure process applications in the manufacturing of advanced semiconductors.

1. Background

  In the semiconductor and flat panel display (FPD) industries*, the ultrapure water being used needs to be supplied without lowering its water quality. The types of pipe materials for this purpose include those that use resin materials hard polyvinyl chloride (PVC), polypropylene (PP), and fluorocarbon resins (polyvinylidene fluoride or PVDF, polytetrafluoroethylene or PTFE, and perfluoroalkoxy or PFA) as well as those that use metallic materials in the form of metal pipes with special surface treatment. Today’s advanced semiconductor industry, with the progress of ultra-miniaturization, requires pipe materials that can suppress the elution of inorganic and organic matter as far as possible.

* The flat panel display (FPD) industry refers collectively to all industries related to the manufacture of flat panel displays, including liquid crystal displays, organic EL displays, and LED displays.

2. PFAS and Its Regulation

  PFAS refers to perfluoroalkyl and polyfluoroalkyl substances, which are difficult to break down in nature and may affect the human body or ecosystems. Among PFAS, the manufacture, import, and such of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) are already prohibited. As of now, PVDF, PTFE, and other materials used in fluorocarbon resin pipes and fittings for ultrapure process applications are not within the scope of regulation in Japan. However, in Europe and the United States, studies are being conducted to comprehensively subject PFAS to regulation. Together with other initiatives, there is a global trend of tighter regulations regarding PFAS.

3. Chronology of Development

  As a pioneer of plastic piping materials, SEKISUI CHEMICAL launched “Eslon Clean Pipe”a hard PVC pipe material for transporting ultrapure water—in 1984. Since then, supported by an impressive track record, the product has been used in a wide range of applications. This time, a special olefin resin pipe material has been developed as a new low-elution material replacing fluorocarbon resins from the perspective of PFAS. In November 2022, a demonstration using an actual ultrapure water manufacturing system was started jointly with Kurita Water Industries Ltd. Compared to existing fluorocarbon resin pipe materials, this special olefin resin pipe material can reduce CO2 emissions during manufacturing by approximately 80%. Furthermore, in response to the global trend of PFAS regulation, SEKISUI CHEMICAL started working on developing PFAS-free pipes and fittings for ultrapure process applications.

4. Future Prospects

  With the establishment of this PFAS-free technology, SEKISUI CHEMICAL will start to formally propose it to customers and will aim for market launch within fiscal 2026. The company will also undertake development toward the early realization of creating valves, gaskets, and other pipe materials that are totally free from PFAS in the area of ultrapure process applications.

Reference: Kurita Water Industries Ltd.