When plotting Yield Stress vs. Log Strain-rate

*When plotting Yield Stress vs. Log Strain-rate

(The EYRING plot, as we call it),* one mostly finds a perfect straight line for all polymers.

This line can be created by running at least 3 tensile tests, at 3 different strain rates (a decade apart each, for instance).

Such plot is incredibly interesting as it reveals the strain-rate sensitivity of your polymer (visco-elastic behaviour).

A low sensitivity (green GOOD line) means the Yield Stress remains high at CREEP rates, leading to good creep performance. But it also remains lower at IMPACT rates, making DUCTILE failure more likely.

A high sensitivity (red BAD line) means that Yield Stress will be lower at CREEP rates leading to more creep (bad). But it also means that Yield Stress will be higher at IMPACT rates, making BRITTLE failure more likely.

What I find unbelievably interesting is that this plot tells us that :

"Polymers that are bad in CREEP tend to be also brittle in IMPACT"

" Polymers that have good CREEP performance, also will show more ductile IMPACT performance"

So contrary to the classical anti-correlation between stiffness and toughness, we find here that both creep and impact move together in a good or bad direction when the Eyring slope changes.

So why don't we focus nearly enough on this simple plot ????
It is just a lack of education and scientific knowledge in our industry.

Discover the amazing Physics of plastic materials in our BIMS seminars.

Check the coming sessions in Copenhagen in 3 weeks (in the comments).

source :, Vito leo

Today's KNOWLEDGE Share : Mainstream Polyester Production Processes

Today's KNOWLEDGE Share

Mainstream Polyester Production Processes

Polyester (such as PET chips and PBT) is one of the most widely used synthetic polymers in textiles, packaging, and engineering plastics. Its industrial production typically involves esterification/transesterification followed by polycondensation.

1. Direct Esterification Process (PTA Method)

Raw Materials: Purified Terephthalic Acid (PTA) + Ethylene Glycol (EG)

This is the most common method in PET production, where PTA reacts directly with EG to form bis(2-hydroxyethyl) terephthalate (BHET), which is then polycondensed into polyester resin.

Advantages:

Shorter process, lower energy consumption.

Lower cost compared with the DMT method.

High product purity and a narrow molecular weight distribution – ideal for polyester fiber and PET bottle chips.

Disadvantages:

Requires high temperature (250–290 °C) and pressure.

Demands high-purity PTA to prevent side reactions.

👉 Application: Over 90% of global PET fiber and bottle chip production adopts the PTA method.

2. Transesterification Process (DMT Method)

Raw Materials: Dimethyl Terephthalate (DMT) + Ethylene Glycol (EG)

This method first converts DMT and EG into BHET through transesterification, followed by polycondensation.

Advantages:

Milder reaction conditions (180–220 °C, atmospheric pressure).

DMT is stable and easy to store.

Disadvantages:

Generates methanol as a by-product, increasing environmental costs.

A more complex process with higher energy consumption.

Broader molecular weight distribution, leading to lower product performance.

👉 Application: Mostly replaced by the PTA process, but still used in PBT resin and some specialty polyester products.

3. Polycondensation Types in Polyester Production

(1) Melt Polycondensation

Conducted at 270–300 °C in the molten state under vacuum.

Pros: Continuous production, efficient, controllable intrinsic viscosity.

Cons: Thermal degradation risk, IV usually ≤ 0.72, high energy demand.

Application: Mainstream for PET bottle resin and polyester fiber chips.

(2) Solid-State Polycondensation (SSP)

Conducted in a solid state at temperatures below the melting point.

Pros: Produces high IV polyester (≥ 0.85), ideal for bottle-grade PET and industrial yarns.

Cons: Long processing time, high energy consumption, requires inert gas protection.

Bio-Based Polyester Production

Uses biomass-based EG or PTA (e.g., corn-derived EG). Hubei Decon can supply bio-based PET based on biomass-based EG. For more information,

source : Hubei Decon Polyester Co., Ltd

Honda unveils the next-gen hydrogen fuel cell

 Honda has just unveiled their next-gen hydrogen fuel cell, and it’s faster, stronger, and more efficient than ever.

This cutting-edge system delivers 3X the power density, 2X the durability, and slashes production costs by 50%, making hydrogen a serious competitor in the EV space.

But it’s not just for cars. Honda’s fuel cell tech is set to revolutionize trucks, buses, construction equipment, ships, and even aerospace. With fast refueling (under 5 minutes), long-range capability (comparable to diesel engines), and zero emissions, it offers a sustainable alternative to battery-electric vehicles, especially for industries that demand high power and long operational hours.

#Honda is also exploring stationary fuel cell power generation, which could provide clean, hydrogen-based electricity for homes, businesses, and remote locations. As governments push for carbon neutrality, could this breakthrough put hydrogen back in the spotlight?

source : Dr.David Novak

Phoebus: framing carbon-fibre fuel tanks for maximum thrust

Phoebus is a European Space Agency (ESA) project together with #ArianeGroup and #MTAerospace. It aims to assess the feasibility and benefits of replacing the metallic tanks on ESA’s Ariane 6 upper stage with #carbonfibre reinforced-plastic tanks. While this lightweight material offers the possibility of saving several tonnes of mass, such an approach has never been implemented before and presents significant technical challenges.

The #Phoebusteam has already proven it is possible, overcoming extremes in material science to contain #liquidoxygen and #liquidhydrogen with carbon fibre. Previous articles have highlighted progress on the #tanks, this article focuses on the surrounding structures, exploring both the challenges and advantages of carbon-fibre reinforced plastic.

A propellant tank is more than a container. The liquids inside must be pumped in and sent to the rocket engines for liftoff, while sensors monitor fuel levels and other parameters. These “feed-through” elements pass through the top and bottom of the tank. These openings also make it possible to clean the tanks and install equipment.

Bolts secure the end covers, but the tanks are made to hold liquid oxygen and hydrogen at temperatures far below –100°C. At these extremely cold levels, metal bolts behave very differently from the carbon material. Because metal and carbon react differently to the cold, they push and pull against each other, which can quickly create a path for leaks even at the tiniest imperfection.

 “The Phoebus team has worked wonders from an initial sketch of a concept to produce a manufactured full-scale part that works,” says #ESA propulsion engineer Kate Underhill, “performing some really cool (pun intended) and complicated cryogenic tests on the way.

MT Aerospace in Augsburg, Germany, started the manufacture in July 2025 of the two covers that will be installed on a full-scale oxygen tank later this year.

With the tanks and the covers sorted, project Phoebus is making significant progress in demonstrating that carbon fibre reinforced plastic is suitable for rocket tanks. These tanks are integral to the rocket stage, connecting to the engine and adding structural stability to endure powerful launch forces.

The Ariane 6 rocket upper stage’s engine is attached to the oxygen tank via a “thrust frame” with pipes running down it from the tanks to the engine. ArianeGroup has come up with an innovation that allows the fuel pipes to be a part of the thrust frame structure – two functions in one part equals a lighter launcher.

This innovative thrust frame started production in December 2024, at various suppliers in Germany, with the assembly to be performed at ArianeGroup in Bremen, Germany in 2026. This innovative #thrustframe is now in production, using the best techniques available worldwide such as including additive manufacturing for the central hub.

source : European Space Agency

Paragraf launches GFET Discovery Kit to simplify graphene biosensor research

UK-based graphene electronics company Paragraf has introduced the GFET Discovery Kit, a package developed to make graphene-based molecular sensing more accessible to the research community. The announcement was made at the I2DM2025 Summit held at Khalifa University in Abu Dhabi.

The kit is intended for researchers investigating graphene field effect transistors in biosensing applications, particularly those who may not have a strong background in electronics. It provides an integrated, ready-to-use platform that removes the usual challenges associated with selecting and configuring hardware.

The GFET Discovery Kit is now available through Paragraf’s online store. It combines the company’s GFET-PV01 devices with a PalmSens EmStat Pico MUX16 data acquisition system and includes pre-configured accessories. Each kit contains four GFET-PV01 sensors, a PiG breakout board, a wiring harness, a mounting plate, a screw kit, and a quick-start guide.

Simon Thomas, CEO of Paragraf, said, “Many researchers in life sciences and materials science want to explore the unique properties of GFETs, but don’t have the electronics background to connect and configure the hardware. We created the Discovery Kit to make graphene molecular sensing accessible. Plug it in, follow the setup instructions in the online user manual and you can begin generating meaningful data almost immediately.”

After assembly, researchers can connect the PalmSens device to a computer and conduct molecular sensing experiments suited to their specific needs. Paragraf also offers downloadable application notes to support particular experimental workflows.

Commenting on the collaboration, Ardy van den Berg, Business Developer at PalmSens, said, “Paragraf’s GFET is precisely the sort of innovative sensor technology the EmStat Pico was designed to enable. We look forward to researchers taking advantage of these tools to expand our collective biosensing knowledge and capabilities.”

Paragraf is recognised as a developer and manufacturer of graphene-based electronic devices, using proprietary methods to produce contamination-free technology for critical applications.

source : Advanced Carbons Council   

Today's KNOWLEDGE Share : Polymers in Cardiology

Today's KNOWLEDGE Share

Polymers in Cardiology

Polymers play a vital role in modern cardiology, providing the flexibility, strength, and biocompatibility required for life-saving devices. From vascular grafts and pacemaker leads to stents and artificial valves, polymeric materials enable the design of components that perform reliably inside the human body under continuous mechanical and biological stress. Advances in polymer science have improved the safety, longevity, and performance of cardiovascular implants, allowing them to mimic natural tissue behavior, reduce complications, and enhance patient recovery.

source : Roberto YAÑEZ

#polymers #medical #cardiology #bioresorbablestrents #valves #catheters

Construction of world's 1st CVD graphene film plant completed

 The Ministry of Trade, Industry and Resources announced on Tuesday that South Korea has completed construction of the world's first mass production facility for chemical vapour deposition graphene film, a material widely used in advanced electronics and #batteries.

The ministry stated that a completion ceremony was held in Pohang for the plant operated by Graphene Square Inc., a domestic producer of graphene film, according to reporting from Yonhap news agency.

A #graphene film is an ultrathin and continuous layer applied in flexible displays, wearable electronics and advanced batteries. It is recognised for its flexibility, transparency and strong electrical and thermal conductivity. According to the ministry, the new facility is expected to support Pohang, traditionally a centre of the steel industry located about 270 kilometers southeast of Seoul, in developing new growth sectors for the region.

source :  Advanced Carbons Council

#cvd #graphenefilm