Today's KNOWLEDGE Share : The Origins of Chemical Notation

Today's KNOWLEDGE Share

Chemical equations are fundamental to chemistry, allowing scientists to represent chemical reactions in a structured, symbolic form. The development of chemical equations was not the work of a single person but rather a gradual evolution over centuries. However, some key figures played significant roles in shaping how we write and understand chemical reactions today.

The Origins of Chemical Notation

Before the concept of chemical equations, early alchemists used symbolic representations to describe reactions, but these were often ambiguous and lacked standardization.

Georg Ernst Stahl (1660–1734) and Phlogiston Theory

In the late 17th and early 18th centuries, Georg Ernst Stahl proposed the phlogiston theory, suggesting that substances released a mysterious element called phlogiston when burned. While incorrect, this idea prompted early chemists to think systematically about chemical transformations.

Antoine Lavoisier (1743–1794) – The Father of Modern Chemistry

The real breakthrough came with Antoine Lavoisier, who is often credited as the father of modern chemistry. In the late 18th century, Lavoisier debunked the phlogiston theory and introduced the law of conservation of mass, stating that matter is neither created nor destroyed in a chemical reaction. This principle laid the groundwork for writing chemical equations.

Lavoisier was one of the first chemists to use a systematic approach to chemical notation. In his 1789 book Traité Élémentaire de Chimie (Elementary Treatise on Chemistry), he introduced a method of representing chemical reactions using elements and compounds, though not in the modern form we use today.

Jöns Jakob Berzelius (1779–1848) – Introducing Modern Symbols

Lavoisier’s work inspired other chemists to improve chemical notation. In the early 19th century, Jöns Jakob Berzelius developed the modern system of chemical symbols, using letters to represent elements (e.g., O for oxygen, H for hydrogen). This innovation made it easier to write reactions concisely and is still used today.

Jean-Baptiste Dumas (1800–1884) and Chemical Equations

French chemist Jean-Baptiste Dumas contributed to balancing chemical reactions, ensuring they followed the law of conservation of mass. His work, along with others, refined the way chemical equations were written.

Wilhelm Ostwald (1853–1932) and Reaction Kinetics

Later, Wilhelm Ostwald and other 19th-century scientists formalized the mathematical representation of chemical reactions, introducing reaction kinetics and equilibrium concepts that further advanced chemical equation notation.

The invention of chemical equations was a collective effort spanning centuries. While Antoine Lavoisier laid the foundation with the conservation of mass, Jöns Jakob Berzelius introduced the modern notation system, and other chemists refined the concept into what we use today.

source : Tiago Vasconcelos

Today's KNOWLEDGE Share : Polymer Degradation

Today's KNOWLEDGE Share

Polymer Degradation

Polymer degradation refers to the process by which polymer materials undergo structural changes, resulting in the loss of their properties and functionality. This degradation can be physical, chemical, or biological, and it impacts the mechanical, thermal, and optical properties of the polymer.

II. Types of Polymer Degradation

1. Thermal Degradation

Thermal degradation occurs when polymers are exposed to high temperatures, causing the breakdown of molecular bonds. This type of degradation is common during processing and manufacturing.

2. Photo-Degradation

Photo-degradation is induced by exposure to ultraviolet (UV) radiation from sunlight. UV light can break down the chemical bonds in polymers, leading to discoloration, brittleness, and loss of mechanical strength.

3. Oxidative Degradation

Oxidative degradation involves the reaction of polymers with oxygen. This process is accelerated by heat and light and results in the formation of free radicals, which further propagate degradation.

4. Hydrolytic Degradation

Hydrolytic degradation is caused by the reaction of polymers with water. This type of degradation is significant in polymers that are used in humid or aquatic environments.

5. Biodegradation

Biodegradation involves the breakdown of polymers by microorganisms. While this can be advantageous for biodegradable plastics, it poses a challenge for conventional plastics that are not designed to degrade in the environment.

III. Factors Influencing Polymer Degradation

Several factors influence the rate and extent of #polymerdegradation:

Temperature: Higher temperatures accelerate the degradation process.

Light Exposure: Prolonged exposure to UV light increases the rate of photo-degradation.

Oxygen: The presence of oxygen facilitates oxidative degradation.

Moisture: Water can promote hydrolytic degradation.

Mechanical Stress: Physical stresses can create micro-cracks, which act as initiation sites for degradation.

Chemical Environment: Exposure to chemicals, such as acids and bases, can catalyze degradation reactions.

source : Plastics Technology

Today's KNOWLEDGE Share : The annoying saddle twist warpage of low MFI polyolefin grades

 Today's KNOWLEDGE Share

147. The annoying saddle twist warpage of low MFI polyolefin grades.

If you ever molded extrusion or blow-molding grades of PP or PE, you have certainly experienced a big warpage problem, stemming from the surprisingly higher than usual IN-FLOW shrinkage.

The graph on the right (similar to my previous post nr. 146) shows that moving to a lower Melt Index increases the chance of freezing more molecular orientation in the part, as a result of the longer relaxation time of low MFI grades.

The graph in the center, from the cited article of 2006, shows the trend of increasing parallel to flow shrinkage with increasing molecular weight of a simple unfilled PP homopolymer.

Note that the three grades are all more viscous than typical in Injection Molding, and they all show a strong anisotropic shrinkage (this is measured on a dog-bone classical tensile bar sample) with larger shrinkage in the flow direction, due to strong molecular orientation.

It is the exact contrary of classical higher flow PP grades where perpendicular shrinkage is higher than parallel !

Finally, as seen on the left drawing (by Covestro), a centrally gated part will warp in a “saddle twist” fashion when the In-FLOW shrinkage is larger than the CROSS-FLOW shrinkage (perimeter wants to be larger than the corresponding radius).

When dealing with these viscous “twisty-warpy” grades one could in theory add just a few % GF that create the opposite effect of lower IN-FLOW shrinkage. Magically, you could suddenly mold a perfectly flat disc, by adding just a pinch of GF to the mix !

A higher packing (qualifying probably as OVERPACKING of the part center) would also flatten these part by creating the opposite warp trend, something illustrated in classical MOLDFLOW® literature more than 40 years ago.

What is your own experience with low MFI grades ?

Please comment and share so that we all learn more about this issue.

source : Vito leo

Ground-breaking Ceremony of Air Conditioning Division - Vignesh Polymers India Private Limited at SIPCOT Industrial Park in tamilnadu (INDIA)

Vignesh Polymers, a pioneer in appliance and automotive component and module manufacturing, today marked a historic milestone with the Ground-breaking Ceremony of its #AirConditioning Division, unveiling its 10th Factory Unit at the SIPCOT Industrial Park, Sriperumbudur Taluk.

The new facility will feature a world-class manufacturing unit, reinforcing the company's commitment to innovation, excellence, and global quality standards. The project involves the establishment of a fully integrated air-conditioning manufacturing facility, designed to support end-to-end production under one roof. The plant will encompass sheet metal fabrication, heat exchanger and copper tubing lines, injection moulding and EPS packing operations as well as the in-house production of propeller and crossflow fans.

source: Business Standard

Today's KNOWLEDGE Share : Touchscreen Car controls

Today's KNOWLEDGE Share

Despite having worked on automotive HMI as a product designer, I prefer physical controls in cars over digital infotainment systems. Sometimes it feels like manufacturers are designing for iPad kids and tech enthusiasts instead of regular A-to-B drivers.

Touchscreen car controls are 2-4 times slower than physical buttons.

Touchscreens increase reaction times +30-57%. Legally drunk drivers: reaction time +12%. Car's touchscreen impairs more than a couple of beers.

Physical controls:

- One motion: turn knob left/right

- Works by feel without looking

- Instant response

- Same location every time

- Works with gloves

- Muscle memory kicks in

- Tactile feedback confirms action

Touchscreen controls:

- Multiple taps through menus

- Requires visual attention to locate

- Lag between tap and response

- Interface changes with software updates

- Fails with gloves/wet fingers

- Must relearn after updates

- No confirmation until you look at display (is haptic feedback is enough?)

VW: "We will never make this mistake anymore. It's a car, not a phone."

The best interface is the one you never have to think about. Especially when you're driving the highway at 100+ km/h.

source : Alex Galagan

Today's KNOWLEDGE Share ; Zinc dispersion in zinc-rich Epoxy

Today's KNOWLEDGE Share

Effective zinc dispersion in zinc-rich epoxy (ZRE) coatings requires over 80 wt% zinc, ensuring electrical contact between particles and the steel substrate for cathodic protection. Standards like ISO 12944 define ZREs as having high zinc content, but effective dispersion and continuous electrical paths are critical for performance, often achieved through careful application and sometimes aided by additives like graphene to create conductive networks that prevent isolation of zinc particles.

Importance of Zinc Dispersion

Cathodic Protection:

The primary mechanism of ZREs is cathodic protection, where zinc particles act as sacrificial anodes, corroding preferentially to protect the steel.

Electrical Contact:

For effective cathodic protection, a continuous electrical pathway must exist between the zinc particles and the steel substrate.

Barrier Protection:

The corrosion products from the zinc also fill micropores in the coating, providing a secondary physical barrier effect against corrosive substances.

Standards and Specifications

High Zinc Content:

ISO 12944 defines a zinc-rich coating as having more than 80 wt% of zinc dust in the dry film to facilitate effective cathodic protection.

Active Electric Channels:

The dispersion must ensure that the zinc particles are not isolated by non-conductive binders or corrosion products, which would hinder the formation of active electronic channels to the metal substrate.

Achieving Effective Dispersion

Pigment Grinding:

The manufacturing process involves a grinding stage to ensure uniform dispersion of zinc pigments, often using bead mills.

Binder and Pigment Ratio:

The correct proportion of binder (epoxy resin) to zinc is crucial. An excess of binder can lead to isolated zinc particles, reducing the coating's effectiveness.

Surface Preparation:

A properly prepared, clean, and often sandblasted steel surface is essential for the zinc-rich coating to adhere properly and form the necessary electrical contact with the substrate.

Factors Affecting Dispersion and Performance

Zinc Particle Size:

While not explicitly a dispersion metric, the particle size of zinc dust is relevant.

Coating Additives:

Materials like graphene can enhance dispersion by promoting the formation of conductive networks within the coating, which improves electrical contact and extends the lifespan of the sacrificial protection.

Curing:

Proper curing conditions after application are necessary for the coating to fully harden and form the necessary barrier and conductive properties.

source : Hussien Elkaluoby

Fibaplast Inspired by Nature – masterbatches with colors and effects inspired by nature

A modern interpretation of natural beauty – with the new Fibaplast – Inspired by Nature product series, we are bringing the fascinating textures and colors of nature into the world of plastics. Inspired by the variety of fine wood grains, the powerful appearance of stone structures and the warm nuances of natural earth tones, high-quality effects are created that give products an distinctive identity.

Extended variety of materials:

Until now, nature-inspired masterbatches have mainly been used in #polyolefins. Finke is now expanding its portfolio to include solutions for #styrenics, enabling even more applications in different material systems. All variants are not only visually impressive, but also technically: they offer good to very good light fastness and therefore guarantee durable, high-quality surfaces.

The targeted play with flow lines, the use of special pigments and additional finishes such as laser marking allow impressive, nature-like structures and a special feel to be achieved. This turns every surface into an experience authentic, unique and high-quality.

Diverse applications with strong designs:

Head of Development and Application Technology Dr. Martin Fritsch explains: “We are noticing that customers are increasingly asking for natural designs in order to visually highlight their products and differentiate themselves more strongly in the market. The first successful applications are already in the cosmetics and furniture industries, where natural effects are particularly appreciated. Our nature-inspired masterbatches are also being used successfully in the toy sector: the special effects give the products a unique look that visually enhances them and makes them stand out from the crowd suitable for children, individual and with a high recognition value.”

Sustainability is also a focus here: many #Fibaplast – Inspired by #Nature masterbatches are already based on recycled materials. On request, we can produce all variants entirely from #recycledrawmaterials – without compromising on quality or aesthetics. In addition, all #Masterbatches are food-safe and therefore open up further application possibilities.

There are also no limits to the imagination when it comes to color design: our experienced colorists develop tailor-made shades and effects that are precisely matched to the customer’s ideas.

source : Finke