#polylactic acid

Tiny Additive Has Big Impact on Compostability of Bioplastic

A simple step dramatically improves the biodegradability of PLA while retaining the plastic’s useful qualities.

Newswise — Compostable plastics could be part of a solution to the world’s plastic waste problem. But currently these materials need industrial composting facilities to break down. In a step toward making a home-compostable plastic, researchers reporting in ACS Central Science have augmented polylactide (PLA) — a widely used biobased and compostable polymer— with a small amount of an additive. Tests show it helps the material degrade substantially faster without sacrificing critical qualities like strength or transparency.  PLA is currently found in products such as food packaging, textiles, and biomedical devices, and it accounts for roughly two-thirds of total bio-based and biodegradable plastics production worldwide. “Composting is considered one of the most effective end-of-life strategies for PLA products, especially food-contaminated single-use products, because it eliminates the need for additional sorting and washing processes,” says Marc Hillmyer, a corresponding author of the paper. This process converts organic waste into environmentally innocuous products such as small organic acids. However, PLA “is only industrially compostable in engineered environments where it degrades over a few months,” he adds. The bioplastic usually needs high temperatures and humidity to break down over practical timescales. 

Study Probes PLA and Wood Dust FFF Composites

Researchers evaluated how wood dust affects PLA parts printed by FFF, and the results could change how makers and manufacturers approach bio-filled filaments. The study, titled “Mechanical properties of PLA–wood dust composites fabricated by FDM,” appears in EPJ Web of Conferences and focuses on a question in consumer and professional 3D printing: can low-cost, renewable fillers meaningfully strengthen or lighten common polymers without reducing print reliability. Wood-filled PLA filaments are not new, but most are marketed for surface aesthetics, lower density, and a pleasant finish rather than structural duty. Decades of polymer–wood composite work in injection molding suggest trade-offs among stiffness, strength, and toughness depending on particle size, loading fraction, and coupling chemistry. FFF adds another layer of complexity: interlayer bonding, bead shape, and raster orientation often dominate performance, and lignocellulosic fillers can bring moisture and thermal degradation into the mix.

'No pumps, no batteries needed': Wearable semiconductor fabric monitors health through sweat

A research team led by Prof. Kim Bong-hoon from the Department of Robotics and Mechatronics Engineering at the Daegu Gyeongbuk Institute of Science and Technology has developed a semiconductor fiber-based wearable sweat sensor that can collect sweat automatically and analyze various biosignals simultaneously without an external power source. They have reported their achievement in Small Structures. Sweat is a useful indicator for real-time health monitoring because it contains various biological information, such as electrolytes and metabolites. However, conventional wearable sweat sensors use microchannel (minute tube) structures or forcefully induce sweating through external stimuli, resulting in unstable skin contact and difficulty reliably collecting the required amounts of sweat.

An enzyme used in laundry detergent can recycle single-use plastics within 24 hours

Scientists at King's College London have developed an innovative solution for recycling single-use bioplastics commonly used in disposable items such as coffee cups and food containers. The novel method of chemical recycling, published in Cell Reports Physical Science, uses enzymes typically found in biological laundry detergents to "depolymerize"—or break down—landfill-bound bioplastics. Rapidly converting the items into soluble fragments within just 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 used for recycling bioplastic materials. This discovery offers a widespread recycling solution for single-use PLA plastics, as 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. Once converted into monomers—single molecules—the materials can be turned into equally high-quality plastic for multiple reuse.

New process enhances thermoplastic blends with polylactic acid

Bio-based thermoplastics are produced from renewable organic materials and can be recycled after use. Their resilience can be improved by blending bio-based thermoplastics with other thermoplastics. However, the interface between the materials in these blends sometimes requires enhancement to achieve optimal properties. A team from the Eindhoven University of Technology in the Netherlands has now investigated at BESSY II how a new process enables thermoplastic blends with a high interfacial strength to be made from two base materials: Images taken at the new nano station of the IRIS beamline showed that nanocrystalline layers form during the process, which increase material performance. Bio-based thermoplastics are considered environmentally friendly, as they are sourced from non-petroleum-based raw materials and can be recycled just like standard thermoplastics. A thermoplastic base material is polylactic acid (PLA), which can be produced from sugar cane or corn. Researchers around the world are working to optimize the properties of PLA-based plastics, for example by mixing them with other thermoplastic base materials. However, this is a real challenge.

A microbial plastic factory for high-quality green plastic

Engineered bacteria can produce a plastic modifier that makes renewably sourced plastic more processable, more fracture-resistant and highly biodegradable even in seawater. The Kobe University development provides a platform for the industrial-scale, tunable production of a material that holds great potential for turning the plastic industry green. Plastic is a hallmark of our civilization. It is a family of highly formable (hence the name), versatile and durable materials, most of which are also persistent in nature and therefore a significant source of pollution. Moreover, many plastics are produced from crude oil, a non-renewable resource. Engineers and researchers worldwide are searching for alternatives, but none have been found that exhibit the same advantages as conventional plastics while avoiding their problems. One of the most promising alternatives is polylactic acid, which can be produced from plants, but it is brittle and does not degrade well.

Scientists 3D print self-heating microfluidic devices

The one-step fabrication process rapidly produces miniature chemical reactors that could be used to detect diseases or analyze substances.

MIT researchers have used 3D printing to produce self-heating microfluidic devices, demonstrating a technique which could someday be used to rapidly create cheap, yet accurate, tools to detect a host of diseases. Microfluidics, miniaturized machines that manipulate fluids and facilitate chemical reactions, can be used to detect disease in tiny samples of blood or fluids. At-home test kits for Covid-19, for example, incorporate a simple type of microfluidic. But many microfluidic applications require chemical reactions that must be performed at specific temperatures. These more complex microfluidic devices, which are typically manufactured in a clean room, are outfitted with heating elements made from gold or platinum using a complicated and expensive fabrication process that is difficult to scale up.

Used coffee pods can be recycled to produce filaments for 3D printing

An article published in the journal ACS Sustainable Chemistry & Engineering brings good news for coffee buffs: the plastic in used coffee pods can be recycled to make filament for 3D printers, minimizing its environmental impact.

The solution was successfully tested by research groups in Brazil at the Federal University of São Carlos (USFCar) and the State University of Campinas (UNICAMP), and in the United Kingdom at Manchester Metropolitan University (MMU).

"We produced new conductive and non-conductive filaments from waste polylactic acid [PLA] from used coffee machine pods. There are many applications for these filaments, including conductive parts for machinery and sensors," Bruno Campos Janegitz, a co-author of the article, told Agência FAPESP. Janegitz heads the Sensors, Nanomedicine and Nanostructured Materials Laboratory (LSNano) at UFSCar in Araras, São Paulo state.