#Polymers

[mindblowingscience]

With significant improvements in transportation technology, the accessibility of fresh food has considerably increased. However, this progress has been accompanied by escalating concerns about food waste during transportation and storage. Globally, around 17% of food at the retail and consumer levels is wasted, resulting in issues like groundwater contamination, hazardous gas emissions, and the spread of infectious pathogens, all contributing to environmental pollution. In a bid to develop efficient, cost-effective, and eco-friendly food preservation technologies, researchers across the world are studying alternatives for the development of packaging materials. Among these, edible coatings made of naturally occurring polymers have shown particular promise.

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[materialsscienceandengineering]

Soft, stretchy 'jelly batteries' inspired by electric eels

Researchers have developed soft, stretchable 'jelly batteries' that could be used for wearable devices or soft robotics, or even implanted in the brain to deliver drugs or treat conditions such as epilepsy. The researchers, from the University of Cambridge, took their inspiration from electric eels, which stun their prey with modified muscle cells called electrocytes. Like electrocytes, the jelly-like materials developed by the Cambridge researchers have a layered structure, like sticky Lego, that makes them capable of delivering an electric current. The self-healing jelly batteries can stretch to over ten times their original length without affecting their conductivity—the first time that such stretchability and conductivity has been combined in a single material. The results are reported in the journal Science Advances.

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[stone-cold-groove]

Illustration detail from a Bakelite Plastics promotional postcard - 1938.

[materiallugy]

What are the materials used in weapons manufacturing?

Materials used in weapons manufacturing are chosen based on their mechanical properties, durability, and suitability for specific applications. The materials used in weapons manufacturing are:

1. Alloys, including steel, aluminum, titanium, nickel, and cooper. 2. Composites, including carbon fiber, glass fiber, and kevlar. 3. Ceramics, including alumina, silicon carbide, and boron carbide. 4. Polymers, including polyamide, polycarbonate, and polyethylene. 5. Specialized Coatings and Treatments, including ceramic coatings, teflon coatings, and phosphate coatings. 6. Explosives and Propellants, including RDX (Cyclotrimethylenetrinitramine), TNT (Trinitrotoluene), and composite propellants. 7. Electronic and Semiconductor Materials, including silicon, and gallium nitride (GaN).

Alloys

High-Strength Steel - Commonly used in the manufacturing of 

Barrels: The main component of a firearm, responsible for propelling projectiles.

Receivers: The housing for the firearm's action, holding essential components.

Slides (pistols): The moving part that houses the barrel and holds ammunition.

Frames (pistols): The base of the handgun, supporting other components.

Bolts and carriers (rifles): Components involved in the firing cycle.

Springs: Essential for firearm operation, providing recoil and return forces.

Steels like 4140, 4340, and maraging steel are known for their toughness, high yield strength, and resistance to wear.............

[mit]

Metamaterials are products of engineering wizardry. They are made from everyday polymers, ceramics, and metals. And when constructed precisely at the microscale, in intricate architectures, these ordinary materials can take on extraordinary properties.

With the help of computer simulations, engineers can play with any combination of microstructures to see how certain materials can transform, for instance, into sound-focusing acoustic lenses or lightweight, bulletproof films.

But simulations can only take a design so far. To know for sure whether a metamaterial will stand up to expectation, physically testing them is a must. But there’s been no reliable way to push and pull on metamaterials at the microscale, and to know how they will respond, without contacting and physically damaging the structures in the process.

Now, a new laser-based technique offers a safe and fast solution that could speed up the discovery of promising metamaterials for real-world applications.

The technique, developed by MIT engineers, probes metamaterials with a system of two lasers — one to quickly zap a structure and the other to measure the ways in which it vibrates in response, much like striking a bell with a mallet and recording its reverb. In contrast to a mallet, the lasers make no physical contact. Yet they can produce vibrations throughout a metamaterial’s tiny beams and struts, as if the structure were being physically struck, stretched, or sheared.

The engineers can then use the resulting vibrations to calculate various dynamic properties of the material, such as how it would respond to impacts and how it would absorb or scatter sound. With an ultrafast laser pulse, they can excite and measure hundreds of miniature structures within minutes. The new technique offers a safe, reliable, and high-throughput way to dynamically characterize microscale metamaterials, for the first time.

“We need to find quicker ways of testing, optimizing, and tweaking these materials,” says Carlos Portela, the Brit and Alex d’Arbeloff Career Development Professor in Mechanical Engineering at MIT. “With this approach, we can accelerate the discovery of optimal materials, depending on the properties you want.”

Portela and his colleagues detail their new system, which they’ve named LIRAS (for laser-induced resonant acoustic spectroscopy) in a paper appearing today in Nature. His MIT co-authors include first author Yun Kai, Somayajulu Dhulipala, Rachel Sun, Jet Lem, and Thomas Pezeril, along with Washington DeLima at the U.S. Department of Energy’s Kansas City National Security Campus.

Keep reading.

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[whats-in-a-sentence]

Table 26.1 gives some examples of polymers formed from compounds related to ethene, along with their common names and most important uses.

"Chemistry" 2e - Blackman, A., Bottle, S., Schmid, S., Mocerino, M., Wille, U.

[jambalaya-on-the-bayou]

god sometimes i wish i was a polymer, life would be so much easier if i was a polymer.

i would just have to carry your groceries and be so helpful to you, or i could play music for you on a second-hand record player, i could brush your teeth for you, i could be so useful as a polymer.

trust me i wouldn’t be like one of those nasty polymers. i wouldn’t be part of the great pacific garbage patch or disintegrate into microplastics in your oceans and in your food. not me sir no i’m not like the other polymers

[thepastisalreadywritten]

World’s first ice cream made from plastic

Reuters | 28 September 2023

The world’s first food made from plastic waste - according to its developer - is vanilla ice cream.

Despite being locked in a freezer in London, she hopes it kickstarts a heated debate about the future of food and the plastic pollution crisis.

The ice cream is actually an art installation called ‘Guilty Flavours’ by artist and designer Eleanora Ortolani, 27, intended to challenge the way we think about plastic waste and what we are - and are not - prepared to eat.

"Guilty Flavours is what I believe is the first sample of ice cream made from plastic waste,” Ortolani told Reuters at Central Saint Martins, part of the University of the Arts London.

“It's coming from the same plastic as we can find in bottles, plastic bottles,” she said.

The process, developed by scientists in Edinburgh, harnesses the metabolic power of bacteria and enzymes to behave as eco-friendly factories to digest polyethylene terephthalate (PET) and turn it into vanillin, the molecule that gives vanilla its flavour.

“There are certain enzymes which do certain chemical reaction,” Dr Joanna Sadler, a biotechnologist at the University of Edinburgh, told Reuters.

“So if you plug those together, you can get through to lots of different chemical products," she said.

Plastic is made of a string of molecules bonded together into what are known as polymers.

Sadler broke those bonds with a hungry microbe, leaving her with molecules that were no longer plastic.

That former PET-soup was then easily processed by another bacteria into vanillin.

Sadler's research, published in the Journal Biochemist in December 2021, focuses on degrading and upcycling plastic and using it as feedstock for microbial growth.

She produced the specially engineered bugs for Ortolani's project but was at pains to point out that the student's ice cream is very much a research project.

It's not currently for human consumption.

"I've even had members of the public email me saying it's irresponsible to encourage people to eat plastic," Sadler said.

"It is really important that we take the safety side of it really, really seriously and we make it very clear that this has to go through exactly the same regulatory processes and food standard processes as any other food ingredient.

And only once it has been through all of those would it go anywhere near any kind of consumer product."

Ortolani, who is from Verona, Italy, said Guilty Flavours was inspired by her frustration with the failure of the recycling system to stop plastic polluting the environment.

It is locked away to highlight what she says is a looming global food crisis.

“We have the tools today to rethink the food system we're living in,” she said.

“This is ready now and today but nobody can really touch it or interact with it because it's not tested for safety yet."

Vanilla, sometimes called 'green gold', is the second most expensive spice in the world after saffron.

UK designer recycles plastic into vanilla ice cream

27 September 2023

Introducing the world's first food made from plastic waste... vanilla ice cream!

Named Guilty Flavours, the ice cream has been designed to provoke viewers into thinking about plastic waste.

The ice cream was developed by scientists in Edinburgh, who used bacteria and enzymes to digest PET plastic and turn it into vanillin -- the molecule that gives vanilla its flavour.

The ice cream is still in its research phase and currently not for human consumption.

[quietimtryingtostudy]

Anyone buying chemistry NCERT (part 2 particularly) for class 12, please ensure you get the latest version as there are some differences in the previous (2018) version and the latest one. In the chapter Polymers, specifically, there are many differences between the 2018 version and the latest version (I have linked the two files, and you can start noticing differences in the first two pages only)

I don’t think the content, or the crux of the content, would be very different, but it is always better if you can get your hands on the latest version.

[chemtexspecialityltd]

Super Absorbent Polymer Polyacrylate based | Chemtex Speciality Limited

Sodium Polyacrylate is a widely accepted super absorbent polymer, that finds extensive usage in various applications like ice gel packs, protective garments, baby diapers, etc., owing to its high water absorption capacity of about 300 – 400 times of its own weight.

Visit-

https://www.chemtexltd.com/products-and-solutions/performance-chemicals/general-chemicals/sodium-polyacrylate/

[mindblowingscience]

Scientists have developed a bioinspired yarn capable of harvesting water from fog, providing an innovative solution to water scarcity in arid regions. By imitating the alternating hydrophobic and hydrophilic patterns seen in desert beetles and the water-transporting abilities of micro/nanoscale one-dimensional spider silk, this double-strand yarn accelerates droplet formation, offering a promising approach to tackling the global water crisis.

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[materialsscienceandengineering]

New plant-based glitter shows no harm to soil organisms

Plastic pollution is everywhere. Each year, over 368 million metric tons of plastics are produced with over 13 million metric tons of it ending up in the soil where it can be toxic to wildlife. Researchers are particularly worried about the environmental impacts of 'microplastics' which are small plastic particles less than 5 mm in size. Microplastics can be produced from products like glitter or when larger objects, including water bottles, break down into smaller and smaller pieces once they're in the environment. Due to their small size, animals can eat microplastics, mistaking them for food, which can cause starvation and malnutrition as well as abrasions to the gastrointestinal tract.

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[your-god-empress-lavender]

Science update or smth:

IDK what's happening anymore, honestly it's all just a blur, but I got the polymer working alright, it's annoying and hard to get it to heat just enough. Like half the times the water is just barely gone and it all just dissolves as soon as I try to clean the polymer and then 48% of the time it's just charred. I have no clue what makes the 2% better than the rest, but the polymer is cured all nice like, so yay. Anyway, in addition to this, I also have been doing a totally safe and smart and not going to horribly fail experiment with adding material to my teeth. Essentially, brushing really well, then swishing with dilute and very slightly basic calcium acetate/chloride/bicarbonate solution, then spit like half of it out and swish with (also dilute) monoammonium phosphate solution. The thing that's hopefully happening is that the two are reacting slow enough that they're forming and crystalizing onto the teeth. IDK how well it's working, but if it is working, I should notice an increase in tooth size in about 8 months. Anyway, the point is that now I can probably sharpen my teeth and it won't be as bad in terms of total material loss.

[med-przemek]

Imperial Lates

Upon experiencing my first Imperial late event, here are a few things that I learnt: 

- My first lecture focused on precision polymer particles by Professor Rachel O’riley. Although typically such nanoparticles are governed by the ratio of hydrophobic and hydrophilic components for self assembly, here; the focus was on crystallisation driven self assembly (CDSA) which overrides this mechanism. DMA seeds are used as the original seeds on which the polymer begins to form through a process known as living polymerisation growth for greater control that leads to platelet like structures. Studying the complexity of assembly was important on exploring how polymer length, composition and chemistry can be altered to rationally tune nanoparticle shape and in turn it’s properties. Novel applications include directing biological interactions, such as cellular uptake, intracellular trafficking and immune response or the ability to modulate hydrogel mechanical and adhesion properties when used as fillers for antimicrobial and tissue engineering purposes. 

- The second talk event was lead by Dr Catherine Kibirige on treating HIV in rural African communities. HIV is particularly difficult to treat and has to be rather suppressed because of it’s elusion from the immune system. Using a continually shifting shield of glycans, it prevent antibodies from detecting and attacking. It also replicates rapidly using reverse transcriptase to develop a pool of diverse HIV strains - called quasi-species - whilst attacking helper T-cells that orchestrate the immune system’s cell signalling. Finally it has a long incubation period and is slow to reveal (typically 5-10 years), where by that point it may have shredded the victims immune system. There are campaigns that have been developed, notably the ongoing UN led campaign of 95-95-95; where 95% people with HIV know their status, then 95% are receiving their treatment and 95% have suppressed their viral load by 2030. Suppression is the best we have at the current moment with no vaccine, with the Undetectable= Untransmittable campaign (U=U), sexual transmissions of HIV can be stopped by lowering the viral load in blood whilst on effective treatment. Dr Kibirige has been a part of the HIVQuant project that is a HIV-1 kit (working on portable solar or battery driven cyclers) that provides a treatment monitoring solution for resource-constrained settings, especially in Africa to minimise monthly hourly trips to district hospitals to meet the 2030 95-95-95 UN target. 

- Vera. AI was the final project that grasped my attention as AI is largely underrepresented in the field of healthcare. Being a hyper-personalised digital platform that focuses on gynaecological, hormonal health management and patient education, this AI tools aims to break women’s health taboos in communicating their medical needs. Focusing on improving patient’s ability to understand and learn, Vera.AI improves patient-doctor communication. This is a project still in it’s early stages but with incorporating ChatGPT in the future, it has colossal potential to democratise women’s health medical data.  

[er-cryptid]