Today's KNOWLEDGE Share : Fatigue test on a Glass filled polymer

Today's KNOWLEDGE Share

Let's imagine we do a fatigue test on a 40% GF filled polymer. Visually, such material will always show what appears to be a brittle failure.

Even a less severe quasi-static tensile test will typically show failure at 1 or 1.5 % strain, which we mentally associate with "BRITTLE FAILURE".

However, you'd be surprised to see to what an extent such failures are largely due to plasticity/ductile mechanisms.

If we do our fatigue test (with a classic stress ratio R=0.1 ) at 1 Hz and then we repeat it on a fresh sample at 2 Hz, very often we will observe that life-time is the same, despite doubling the number of cycles ! This indicates that failure is essentially controlled by the underlying creep and accumulated plastic strain. A totally ductile mechanism !

If we were to observe failure two times faster, i.e. at the same number of cycles, this would point towards a dominant crack growth/brittle mechanism.

In real life, we may also find something in between, demonstrating that failure mechanisms are often the result of concurrent damage mechanisms involving plasticity and cavitation. This is what modern "progressive damage" models (e-Xstream engineering, part of Hexagon’s Manufacturing Intelligence division for instance) will implement.

source:Vito leo

My speech at Ahmdabad University in August 2024

Join me on 11th August for Day 3 of #CINCE2024 Conference in Ahmedabad to hear my speech on Composites in the Hydrogen Economy that addresses significant challenges in the composites storage systems and the future of the hydrogen economy that is going to enhance our lives through zero carbon emission on the earth.

There are quite a number of presentations from the Peers in the Polymer Composites Industry and attend the sessions on various technologies and interact with leading experts in the field of composites.”

Register here  https://lnkd.in/gTnt9JGX

Offering process efficiency solutions for the environmental impact emission reduction.Looking forward to seeing everyone at the conference.

#polymers #type4cylinders #composites #plasticsindustry #hydrogen #compositematerials #cince2024 # #future #hydrogeneconomy  #storagetank #conference2024 #india #cgd #pipeline #naturalgas #gas #greenhydrogen #electrolysers #ccus

#alternativeenergy  #renewableenergy #cleanenergy #netzero #carbonfiber

New Method Recycles Unsaturated Polymers Using Oxygen and Light

 A groundbreaking study has been published in the esteemed journal, Cell Reports Physical Science, showcasing a novel method for the recycling of unsaturated polymers such as rubber and plastics.

The paper introduces a process using oxygen and light to help break down the polymers naturally. It is authored by Dr. Junpeng Wang, assistant professor of polymer science at The University of Akron, and a team of current and former students including Dr. Hanlin Chen ‘23, Dr. Devavrat Sathe ’23, Xin Guan and Puyang Zhang,

Introducing Unsaturation to Enhance Reactivity of Polymers:

Since the 1950s, the mass production of plastics has resulted in the creation of approximately 8.3 billion metric tons of polymers. Unfortunately, the majority of these polymers have been discarded or incinerated, leading to significant environmental contamination. Only 600 million metric tons have been effectively recycled. The stability and durability of commercial polymers, particularly polyolefins, which constitute over half of global polymer production, present significant recycling challenges due to their hydrocarbon backbone.

The new research focuses on introducing unsaturation to enhance the reactivity of these polymers, thus facilitating their recycling. Traditional methods for oxidative cleavage of alkenes, such as ozonolysis, epoxidation, and permanganate oxidation, while effective, often require environmentally unfriendly, energy-intensive conditions that are difficult to scale up. These methods also generate unwanted by-products, posing additional environmental challenges.

In contrast, the ideal oxidant for such processes would be O2, due to its abundance, green nature, and accessibility. However, previous methods using O2 for polymer degradation have been slow and not well controlled for recycling purposes. This study pioneers a controlled, efficient method for breakdown using a catalyst that, when activated under light, successfully breaks down the polymers at room temperature without requiring elevated temperatures or pressures.

Wang and his team's work opens new avenues for the recycling of polymers, addressing one of the most pressing environmental issues of our time. This research not only enhances our understanding of polymer degradation but also provides a practical, scalable solution for recycling unsaturated polymers.

Source: The University of Akron/omnexus.specialchem.com

Today's KNOWLEDGE Share :Warpage of Glass filled Nylon

Today's KNOWLEDGE Share

Warpage of a GF filled nylon part is extremely dependent on temperature and moisture uptake.

Temperature increase is responsible for matrix expansion (negligible for the fibers though), and moisture uptake produces matrix swell (again GF does not care much).

So if a part is warped when dry as molded at room temperature (that is what simulation codes will predict for you !!) it will tend to "UNWARP" as you heat the part or let it uptake moisture.

This effect can perfectly be simulated, if you account properly for the anisotropic elastic properties and fiber orientation and know the swell rate with water uptake.

For temperature induced UNWARP you will need detailed CTE (T) in x, y and z though to get it right ! Those CTE's, with the needed level of detail, are not available directly from Flow Analysis codes for the moment, but e-Xstream engineering, part of Hexagon’s Manufacturing Intelligence division Digimat software can provide those.

source:Vito leo

Today's KNOWLEDGE Share:CYANATE ESTER

Today's KNOWLEDGE Share

CYANATE ESTER:

Cyanate ester resins are a special class of polymeric materials whose molecules contain structural units of cyana(-CN) and carbonyl groups(-C00). Cyanate esters exhibit attractive physical, electrical, thermal, and processing properties. Blends with epoxy and bismaleimide are common.

Cyanate esters bear basically two cyanate groups (-OCN) attached to an aromatic ring. Also, aryl cyanate esters with additional allyl groups are known, e.g., 1-allyl-2-cyanatobenzene. Cyanates are formed by the reaction of phenols with cyanogen halides.

Cyanate ester resins are superior to epoxy resins, phenolic resins, and bismaleimide resins. They combine the advantages of epoxies, the fire resistance of phenolics, and the high-temperature performance of polyimides. Dicyanates of bisphenol derivatives are currently used in composites with established reinforcements such as carbon fiber, glass fiber, silica cloth, pitch-based graphite fibers.

Properties of Cyanate Ester Monomers:

Low Melt Viscosity

Good Solubility in Common Solvents

Compatible with Other Resins

Properties of Cured Resins:

High Tg

Low Thermal Expansion

Low Dielectric constant, Dissipation factor

Good Electrical Insulation

Applications:

Electronic Materials: Printed Wiring Boards for high frequency devices, Thermal Conductive Materials, etc.

Structural Materials: FRPs, Adhesives, etc.

Cyanate ester resins are currently used for many important applications such as high-temperature adhesives, and advanced composite matrices in the aerospace and automotive industry. A unique combination of properties such as high temperature stability and chemical resistance, low moisture uptake and low dielectric constant in the cured state, as well as low viscosity in the uncured state has led to their use in low-volume high-performance applications. The most common thermoplastic tougheners for epoxy systems are polysulfones (PSF), polyetherimides (PEI) or polyethersulfones (PES.

cyanate ester resins are used for high-temperature composites and adhesive applications. These systems can provide high glass transition temperatures (Tg = 170 - 350ºC), low water absorption and low dielectric properties. These products are typically used in aerospace and space applications, high-speed circuit boards, electronic chip adhesives and encapsulants, and syntactic foams.

Moisture resistance was improved by blending bisphenol A dicyanates with epoxy resins to reduce the amount of ester linkages in the resulting copolymer.

In order to enhance the moisture resistance of cyanate ester resins, modifiers containing silicon or fluorine moieties were introduced.

A high temperature resistant novolac cyanate ester was blended with polyethersulfone (PES) with different molecular weights using the solvent-free approach.

Key Players:

Huntsman

Lonza

Techia Corporation

Koniklijke TenCate

Cytec

Kuraray

Hexcel

Jiangdu Maida Group

Toray

Isola Group

Adeka

SGL Carbon

Gurit

Syensqo

Mitsubishi Gas Chemical

source:Mitsubishi

Suzuki Motor Corporation and Banas Dairy to invest over Rs 250 crore to establish four biogas plants in Gujarat

Suzuki Motor Corporation and Banas Dairy will invest over Rs 250 crore to establish four biogas plants in Gujarat. The project is aimed at making fuel for automobiles by refining methane from biogas. The biogas is created by fermenting cow dung, and the resulting liquid fertilizer will be used in agriculture, according to Banas Dairy Chairman Shankar Chaudhary, reported Ahmedabad Mirror.

An agreement between Maruti Suzuki and Banas Dairy will be inked for the same.The four biogas plants, set to begin operations in 2025 in Banaskantha district, will have a combined biogas production capacity of 500,000 liters. Each plant will also feature a biogas-filling station.

Suzuki’s commitment to achieving carbon neutrality through proactive biogas production initiatives will be highlighted during the visit of Suzuki President Toshihiro Suzuki to Banaskantha. He will tour the biogas plant, the cheese plant at Palanpur dairy, and the potato processing plant in Sanadar.

In December 2022, Suzuki signed a Memorandum of Understanding (MoU) with NDDB and Banas Dairy to launch a Biogas Demonstration Project. Additionally, Suzuki Research and Development in India (SRDI), NDDB, and Banas Dairy will sign an agreement for technical research in biogas technology, with plans to design a more efficient plant in Tharad.

Last year, Suzuki, NDDB, and Banas Dairy expressed interest in the Banaskantha biogas plants, aiming to reduce greenhouse gases and advance carbon neutrality through these proactive initiatives.

source:bioenergytimes.com

Liqcreate introduces new 3D printing resin “Rigid Pro” for demanding applications

Liqcreate, a manufacturer of 3D printing materials, has introduced a new technical 3D printing resin called Liqcreate Rigid Pro. This resin offers high chemical resistance, good temperature resistance and high strength and rigidity. These properties make it ideal for a wide range of applications in the engineering, automotive, electronics and oil and gas industries.

Liqcreate Rigid Pro is a rigid photopolymer resin that can be processed on most resin-based 3D printers. It is compatible with Digital Light Processing (DLP), Liquid Crystal Display (LCD) and laser-based 3D printing systems in the 385-420 nm range. This broad compatibility ranges from entry-level systems from Anycubic, Elegoo and Creality to professional systems such as Asiga, Nexa3D and UnionTech Martrix.

A key advantage of the Rigid Pro resin is its chemical resistance. Parts made with this resin can withstand a wide range of chemicals such as mild acids and bases. In addition, the material is also resistant to petrol and diesel, making it suitable for applications in the oil and gas and chemical industries. Customized chemical resistant parts can now be designed and printed within days at unprecedented costs.

For applications requiring high temperatures, Liqcreate Rigid Pro can achieve a heat resistance temperature (HDT-B) of 77°C through simple UV post-curing. With a Formlabs Formcure unit at elevated temperatures, this can be increased to 91°C and can even reach 109°C with an optional thermal post-curing step. This temperature resistance makes the resin suitable for automotive parts under the hood as well as medium temperature resistant castings and molded shells.

The Rigid Pro resin combines chemical and temperature resistance with a high flexural strength of 110 MPa. This opens up a wide range of applications in customer-specific machining and factory equipment. Parts exposed to static loads in the engineering industry can now be designed, 3D printed and post-processed within a day, without the need for a large stock of spare parts.

For OEM partners, the Rigid Pro resin can be renamed and optimized for different applications and 3D printers. In addition to its own resin range, Liqcreate offers a development service for customized formulas to meet specific properties. This enables customers to request polymers with precise properties that affect both the printing speed and the properties of the finished part.

Thanks to its own R&D facilities, Liqcreate is able to quickly scale up the production of customized resins. The company’s independence ensures a fast time to market and avoids delays that could arise from competition or conflicts of interest.

source:Liqcreate/3dprintr.com