Today's KNOWLEDGE Share:PEEK FOR HIGH PRESSURE SEALS

Today's KNOWLEDGE Share

3 REASONS YOU SHOULD CONSIDER PEEK FOR HIGH PRESSURE POLYMER SEALS

1.STRENGTH:

PEEK seals can withstand pressures up to 30 ksi (207 MPa). This is due to PEEK’s combination of high strength and high modulus. 

The three different grades of PEEK: Virgin PEEK,30% Glass fiber reinforced PEEK, and 30% Carbon fiber reinforced PEEK.

Tensile Strength: 14 ksi,18.9 ksi, 31 ksi

Tensile Modulus:507 ksi,1600 ksi,3050 ksi

2.OPERATING TEMPERATURE:

High pressure applications often go hand in hand with extreme temperatures. Fortunately, PEEK offers a wide operating temperature range. It works for cryogenic applications down to -100°F and still retains its key mechanical properties in temperatures up to 450°F. 

3.CHEMICAL RESISTANCE:

Another reason for PEEK’s popularity in high-pressure applications involves its chemical resistance. Many times these same high-pressure environments involve harsh or caustic chemicals that can compromise the physical properties of even the most outstanding polymers. PEEK, on the other hand, can retain its strength even in the presence of harsh chemicals with just a few exceptions.

PEEK’s combination of strength and stiffness makes it a prime choice for high pressure applications, but when that is combined with its resistance to chemical attack and operating temperature range, PEEK quickly begins to stand out as a first choice for high pressure polymer seals. Combine that with its resistance to both wear and creep, and PEEK is definitely a winner when it comes to intense, demanding seal applications. 

source:Advanced EMC technologies

Today's KNOWLEDGE Share:High and low shear rate changes in Rheology

Today's KNOWLEDGE Share

If a relatively high Mw grade flows from thin to thick, as shown in the picture, and if the time needed to fill the thick section is way shorter than the average polymer relaxation time, the polymer will not be able to reach its higher viscosity (corresponding to higher thickness/lower shear-rate). I am assuming here the polymer reached equilibrium low viscosity in the thin section, say for instance because it is much longer.

Any pressure prediction not accounting for transient rheology would then overpredict the pressure to fill.Of course the diverging flow will further complicate the situation and mess with the molecular orientation created in the thin section, but to what extent ?

Since this is more of a reasonable "conjecture", don't take this for granted, and discuss or share your opinion in the comments.

There are hundreds of Rheology papers on the "4:1 contraction flow".

Not sure I have ever seen any on the..."1:4 expansion flow" !

source:Vito leo

Covestro Develops High Heat Resistant Copolycarbonate for Medical Industry

Overmolding polycarbonate with liquid silicone rubber (LSR) is commonly used to produce respiratory masks and other medical devices requiring molded-in seals. Now, Covestro has developed Apec® 2045 – a copolycarbonate with the highest heat resistance. It enables molders and medical OEMs to significantly slash production time and cost. This does not sacrifice quality, performance or appearance.

Supports Close- and Open-loop Recycling:

"We work closely with our healthcare customers and recognized that we could offer a polycarbonate made for highest curing temperatures in silicone over-molding, helping them more than double production volumes in the same amount of time due to shorter cycle times," said Pierre Moulinie, Global Healthcare Technology lead, Covestro LLC.

Apec® 2045 copolycarbonate also offers other important benefits for this market. These include:

Durability: Tough engineering plastic with the highest heat resistance in the medical polycarbonate portfolio

Transparency: Produces transparent parts with high optical clarity

Biocompatible: Biocompatibility testing according to ISO 10993-1 and USP Class VI for contact of 30 days or less

Sterilizable: Supports sterilization methods most prevalent in the healthcare industry, including irradiation, autoclave and hot air

Processability: Consistent and efficient processing

Using this new material may help customers meet sustainability goals. It enables circular business models by supporting close- and open-loop recycling. It also allows for the possibility of attributed bio-circular content.

Attendees at MD&M West, February 6-8 in Anaheim, California, can visit the Covestro booth (#2221). There they can learn how Covestro's materials push boundaries in healthcare applications.

Polycarbonates from Covestro are found in some of modern technology’s most essential medical devices. They play a major role in developing next-generation, life-saving technology. These exemplify the innovation, safety and biocompatibility known and trusted worldwide. This is because they are used where strength, clarity and toughness are necessary.

"Our experts provide support every step of the way," he continued, “helping our customers calculate possible savings when switching to this new high-heat Apec® copolycarbonate grade – for example, simulating material performance in specific applications and calculating cost benefits with our LSR calculator tool.”

Souce:Covestro/omnexus.specialchem

Today's KNOWLEDGE Share : POLYAMIDE-IMIDE (PAI)

Today's KNOWLEDGE Share

POLYAMIDE-IMIDE (PAI)

Polyamide-imide (PAI) is an amorphous, opaque thermoplastic that can be melt processed using conventional injection molding, extrusion or compression molding techniques.

PAI or polyamide-imide is one of the most resistant polymers on the market today. It draws its notoriety from its resistance. Without additives, polyamide-imide has the ability to withstand extreme temperatures. This material remains unchanged even when exposed to a temperature of 270°C.

Furthermore, PAI is a very durable plastic, has low frictional resistance and is resistant to UV, gamma and X-rays.

SPECIFIC GRAVITY :1.41

TENSILE STRENGTH 21,000 psi

FLEXURAL STRENGTH  33,000 psi

FLEXURAL MODULUS  600,000 psi

COEFFICIENT OF LINEAR THERMAL EXPANSION :1.7 (D696)

WATER ABSORPTION (Immersion 24 hours):0.30 (ASTM D570)

GLASS TRANSITION TEMPERATURE :280 °C

MAX CONTINUOUS SERVICE TEMPERATURE IN AIR :500 °F

HEAT DEFLECTION TEMPERATURE @ 264 psi :532 °F

DIELECTRIC STRENGTH:600 (D194)

When PAI is melt-processed, its high glass transition temperature, non-Newtonian flow over a wide processing shear range and its amorphous morphology pose many significant challenges. Among the most challenging are:

*Narrow processing window with processing temperatures greater than 600 F

*Melt viscosity that is highly temperature and shear rate sensitive

*As a polycondensation polymer, PAI is highly moisture sensitive and must be thoroughly dried and maintained during melt processing to prevent molecular weight and thermal-mechanical property degradation

*Thermal cure for 20 or more days at 500 F to optimize properties after melt processing.

To achieve optimum properties, PAI must be processed under closely controlled conditions and then thermally cured to advance its molecular weight through a staged heat cycle up to 500 F. The curing process completes the imidization process and builds molecular weight via polycondensation. Water is the condensation by-product which must be removed in order to advance the MW and Tg. Since polycondensation is a two-way reaction, it is critical to remove water to advance the reaction. If water is present at temperatures at or above the glass transition temperature, hydrolysis and property loss can occur.

Polyamide-imide / PAI is used for manufacturing of:

Moving parts, track rollers, bearings, gears, bearing washers.

Bushings, vanes, seals, jacks and panels, electrical components and bushings, gears, plugs,connectors, parts of pumps, seals, valves,items furnaces conveyors, hydraulic valves, air grilles, security features

clutch seals bearing and sliding bearing portion.

PAI - polyamide-imide is used for runners, guide rollers in printers, copiers.

PAI available in Unfilled Grade,Graphite filled,glass filled,carbon filled PAI grades are available in the global market to meet the end application requirements.

Major Brands:Tecator, Torlon, Duratron, Kermel

source:solvay/brakeplastics/ptonline.com

New Method Uses Enzymes from Laundry Detergent to Recycle Single-use Bioplastics

Scientists at King’s College London have developed an innovative solution for recycling single-use bioplastics. Single-use plastics are commonly used in disposable items such as coffee cups and food containers.

This chemical recycling method uses enzymes found in biological laundry detergents to depolymerize landfill-bound bioplastics.

84x Faster Breakdown than Conventional Approach

Within 24 hours, the process achieves full degradation of the bioplastic polylactic acid (PLA). The approach is 84 times faster than the 12-week-long industrial composting process.

The team of chemists at King’s found that in a further 24 hours at a temperature of 90°C, the bioplastics break down into their chemical building blocks.This offers a widespread recycling solution for single-use PLA. Once converted into monomers the materials can be turned into high-quality plastic for multiple reuse.

Current rates of plastic production outstrip our ability to dispose of it sustainably. According to Environmental Action, it is estimated that in 2023 alone more than 68 million tons of plastic ended up in natural environments. This is due to the imbalance between the huge volumes of plastics produced and the recycling capacity. A recent OECD report predicted that the amount of plastic waste produced worldwide is on track to almost triple by 2060, with around half ending up in landfill and less than a fifth recycled.

"Being able to harness biology to deliver sustainable solutions through chemistry, allows us to start thinking of waste as a resource so that we can move away from oil and other non-renewable sources to create the materials we need for modern life," Dr Alex Brogan, lecturer in Chemistry.

Sustainable Blueprint for Recycling Single-use Bioplastic

While bioplastics are a more sustainable choice, production costs are high. Mechanical recycling methods are inefficient, generate CO2 and do not produce high-quality materials. These ‘green’ plastics primarily end up in landfill after just one use, causing many retailers to revert back to using oil and fossil-based materials.

The speed at which the bioplastics breakdown using this new method could revolutionize plastic production. It offers an efficient, scalable and sustainable blueprint for recycling single-use bioplastics. The research opens up the opportunity for a sustainable, circular economy that stamps out the production of fossil-based plastics. It also tackles the huge volume of plastic waste that ends up in landfill and natural environments.

Dr Alex Brogan, lecturer in Chemistry at King’s College London said, “The inspiration for this project came from a problem with bioplastics used in medical and surgical products degrading in the body. We’ve turned this problem around and applied it to the issue of recycling the single-use bioplastics we use in our everyday lives using a common enzyme found in biological laundry detergent.”

"Being able to harness biology to deliver sustainable solutions through chemistry, allows us to start thinking of waste as a resource so that we can move away from oil and other non-renewable sources to create the materials we need for modern life.”

The aim is now to improve the recycling of other common plastics, like in single-use water bottles, film and sheet plastic packaging, and clothing.

"Our research marks the first step in developing new technologies in waste management for recycling bioplastics that are of equal quality to the virgin product," Susana Meza Huaman, PhD researcher on the project.

Susana Meza Huaman, PhD researcher on the project at King’s College London, said, “Our research marks the first step in developing new technologies in waste management for recycling bioplastics that are of equal quality to the virgin product. Until now this has been a major challenge in plastics recycling, as while bioplastics are made of biological materials, they are not all compostable and most current recycling methods are inefficient.”

"Our chemical approach significantly speeds up the degradation of bioplastics, enabling them to be recycled and reused.”

Source: King's College London/omnexus.specialchem

Today's KNOWLEDGE Share: BISMALEIMIDE RESIN (BMI)

Today's KNOWLEDGE Share

BISMALEIMIDE RESIN (BMI):

Bismaleimides monomers are synthesized from maleic anhydride and an aromatic diamine and then, the resulting bismaleamic acid is cyclo-dehydrated to a bismaleimide resin.BMI resins are a type of high-performance thermosetting polymer that possesses exceptional mechanical and thermal properties. These resins are characterized by their high heat resistance, flame resistance, and dimensional stability, that are suitable for a wide range of applications mainly withstanding extreme conditions.

BMI is easy processing by autoclave, platen press, and compression molding techniques,

excellent mechanical properties up to 250 °C,

good solvent resistance,

excellent performance in hot and wet conditions

superior flame and radiation resistance,

low smoke and toxicant emissions.

Processing techniques include prepregging resin transfer molding (RTM), filament winding,compression molding, powder coating and pultrusion.

The drawback of the BMI resins is Fracture toughness.This hampers its use in aerospace applications.To improve the toughness,a flexible monohydric aliphatic amine (MAA) can be added with neat BMI resins to increase the toughness of the resin.The morphology of MAA modified BMI observed via scanning electron microscopy (SEM).Various formulations tried in a few research projects over the decades,at 1% MAA adding in the formulation,the elongation at break MAA-modified BMI increased by 32.3 % when compared with neat BMI.The same way flexural strength of MAA modified BMI showed increasing 30%.This results showed increase usage in aerospace applications in the recent years.

There is a couple of research that have been taking place in adding inorganic fillers such as Nano Sio2,Carbon Nano Tube (CNT) and Graphene with the modification of BMI resin system with Carbon fiber,Kevlar,Basalt and Glass fiber.The results are breathtaking and leads to lot new more research to improve the toughening properties of BMI composite laminates.

Another research that impressed me was producing bismaleimide from renewable carbon content through multi functional phosphate(TAMPP) from clove oil.

A multi-functional phosphate (TAMPP) was synthesized from renewable eugenol through aqueous-phase synthesis, of which the renewable carbon content is as high as 100%. TAMPP was used to partly or totally replace petroleum-based 2,2′-diallylbisphenol A (DBA) for modifying 4,4′-bismaleimidodiphenylmethane (BDM), and then four bismaleimide (BMI) resins (BDTP or BTP) were developed. Compared with traditional DBA modified BDM resin (BD), BTP has better integrated properties including a higher renewable carbon content (45.0%), an approximately 70 °C higher glass transition temperature (Tg > 380 °C), excellent flame retardancy and good mechanical properties. 

Some of the leading key players are Huntsman,Evonik,Renegade Materials,Solvay, Qinyang Tianyi Chemical,Hos-Technik,Honghu Shuangma Advanced Materials,Hexcel etc.

Source:Acs publications/evonik

INEOS’ Bio-based HDPE Used to Create Gas Pipeline

INEOS produced bio-based high-density polyethylene (HDPE) has been used to create the world’s first fully sustainable gas pipeline. Installed by French gas utility network operator, GRDF, the pipeline only uses the low carbon footprint polymer.

Made from Wood Processing Residues from Paper Industry:

The new pipeline is in Clermont Auvergne Métropole, France. It is part of a GRDF program to “green” pipelines in parts of the region. The goal is to reduce their carbon footprint. One kilometer of pipeline will be laid across three sites in the metro area gas network.

The pipeline uses bio-based, certified HDPE supplied by INEOS Olefins & Polymers Europe. It’s made from wood processing residues from the paper industry, which are transformed into tall oil, a bio-naphtha. INEOS Cologne turns the tall oil into bio-ethylene. It is transported to INEOS’ polymer plant in Lillo, Belgium. There it makes the bio-based HDPE.

The result is a polymer with a much lower carbon footprint than conventional, fossil-based polymers. It is recognized by ISCC, an independent, third-party organization. It has certified that producing the pipes met ISCC Plus standards. This was by replacing fossil fuel-derived feedstocks.

Potential to Repeat Innovation for Other Gas and Water Pipelines:

Importantly, the bio-polymer has the same technical characteristics as conventional polymers. This enables partners like GRDF to meet high safety standards. At the same time, it reduces the environmental impact of networks operated for local authorities. It also creates potential to repeat the innovation for other gas and water pipelines.

All polymers offered by INEOS Olefins & Polymers Europe are also 100% recyclable, alongside the lower carbon footprint associated with the bio-based HDPE.

Rob Ingram, INEOS Olefins & Polymers North CEO, said, "Our congratulations to GRDF for this world first. At INEOS, we’re very proud to play a part in this game-changing innovation. Alongside the work we are doing to drive down emissions and reduce plastic waste in the polyolefins industry, it’s another example of our commitment to working with partners to develop efficient, lower emission solutions for transporting important utilities and goods around Europe’s cities."

Source:Ineos/omnexus.specialchem