Degradable packaging materials: Sources, application and decomposition routes

There are many biodegradable and recyclable packaging materials available, alternatives for plastics: paper and cardboard; biodegradable polyethene (degradable due to additives incorporated during production, whose role is to lead to the polyethylene breakdown into CO2, H2O, biomass and minerals when in landfill) and biodegradable plastic (made from renewable biomass-biopolymers in a relatively energy-efficient process). The decomposition routes of degradable materials are reflected in the degradation for which realization a physico-chemical stimulus is required and biodegradation for which microorganisms are responsible. The global biodegradable plastic market was valued at $1.6 billion in 2019 and it is expected to reach $4.2 billion by 2027. The largest segment by application of biodegradable materials is in packaging with a market share of more than 60%. Some examples of degradable packaging existing on the market will be presented in the paper.

Biodegradable materials for bone defect repair

Compared with non-degradable materials, biodegradable biomaterials play an increasingly important role in the repairing of severe bone defects, and have attracted extensive attention from researchers. In the treatment of bone defects, scaffolds made of biodegradable materials can provide a crawling bridge for new bone tissue in the gap and a platform for cells and growth factors to play a physiological role, which will eventually be degraded and absorbed in the body and be replaced by the new bone tissue. Traditional biodegradable materials include polymers, ceramics and metals, which have been used in bone defect repairing for many years. Although these materials have more or fewer shortcomings, they are still the cornerstone of our development of a new generation of degradable materials. With the rapid development of modern science and technology, in the twenty-first century, more and more kinds of new biodegradable materials emerge in endlessly, such as new intelligent micro-nano materials and cell-based products. At the same time, there are many new fabrication technologies of improving biodegradable materials, such as modular fabrication, 3D and 4D printing, interface reinforcement and nanotechnology. This review will introduce various kinds of biodegradable materials commonly used in bone defect repairing, especially the newly emerging materials and their fabrication technology in recent years, and look forward to the future research direction, hoping to provide researchers in the field with some inspiration and reference.

Perlakuan Termomekanik Paduan Mg-Gd Sebagai Material Implan Mampu Luruh

Paduan Mg-1,6Gd (wt%) mempunyai potensial sebagai material implan yang mudah larut dalam tubuh. Penambahan Gd kedalam magnesium dan selanjut di proses melalui termomekanik bertujuan untuk memperbaiki sifat-sifat mekanik yaitu kekerasan, kekuatan, ketangguhan dan keuletan dan juga dapat mengontrol laju korosi dalam lingkungan biologis. Perubahan mekanik yang terbentuk akibat penambahan sedikit Gd (1,6wt%) kedalam Mg kemudian diproses termomekanik melalui ekstrusi dan rolling yang dikaitkan dengan hasil strukturmikro melalui ukuran butir dan phasa. Proses termomekanik dilakukan pada temperatur rekristalisasi (400-550 °C) paduan Mg-1,6Gd dengan reduksi 95 %. Pemeriksaan dilakukan di skala labor dengan menggunakan tahap-tahap metalografi dan pengujian tarik dengan ukuran sample yang standar ASTM E8. Uji kekerasan dengan menggunakan alat uji Hardness Vicker dengan berat 300 gram dan ditahan selama 15 detik. Pemerikasaan ini dilanjutkan dengan pengujian laju korosi dengan menggunakan cairan infus. Hasil menunjukan bahwa terjadi perubahan ukuran butir yang siknifikan pada paduan Mg-1,6Gd setelah proses termomekanik terutama pada proses ekstrusi panas yaitu mencapai 14 µm, namun kekerasan tertinggi terdapat pada proses pengerolan yaitu mencapai 50 HVN. Adanya sejumlah presipitat ditemui pada strukturmikro yang dapat mempengaruhi kekerasan akibat pengerolan. Sifat-sifat mekanik paduan Mg-1,6Gd juga dipengaruhi oleh presipitat, dimana kekuatan tertinggi adalah 197 MPa pada pengerolan dibanding ekstrusi hanya mencapai 187 MPa. Meskipun demikian keuletan terbesar dimiliki oleh pengerolan yaitu 26 %, sementara ekstrusi hanya mencapai 24 %. Pada pengujian korosi, pengerolan memiliki laju korosi yang lebih tinggi dibanding laju korosi ekstrusi yaitu 5,7 mmpy dalam larutan Ringer. Kedua proses termodinamik ini mempunyai peluang sebagai material implan yang mudah larut dalam tubuh, namun pengerolan lebih di rekomendasi baik dari sifat mekanik maupun laju korosi yang lebih terkontrol. Mg-1,6Gd (wt%) alloys has potential as a degradable materials implant. The addition of Gd in magnesium and then subsequently processed through thermo-mechanics aims to improve mechanical properties such as hardness, strength, toughness, ductility and can also control the rate of corrosion in the biological environment.Mechanical can be changed by the small addition of Gd (1.6wt%) into Mg are then is processed through extrusion and rolling which are associated with grain size and phase. The thermomechanical process was carried out at a recrystallization temperature (400-550 °C). Mg-1,6Gd alloys was hot rolled with a reduction of 95%. The examination is carried out at a labor scale using metallographic steps and tensile testing with a standard of ASTM E8. Hardness test use the Hardness Vicker with 300 grams and held for 15 seconds. This examination is followed by testing the rate of corrosion using intravenous fluids. The results showed that there was a significant change in grain size in the Mg-1,6Gd alloys after the thermomechanical process, especially in the hot extrusion which reached 14 ?m, but the highest hardness was found in the rolling process which reached 50 HVN. A number of precipitates are found in micro structures that can affect violence due to rolling. The mechanical properties of the Mg-1,6Gd alloys are also affected by the precipitate, where the highest strength is 197 MPa on rolling compared to extrusion reaching only 187 MPa. However, the greatest tenacity is owned by rolling, which is 26%, while extrusion only reaches 24%. In corrosion testing, rolling has a higher corrosion rate than the extrusion corrosion rate of 5.7 mmpy in Ringer's solution. Both of these thermodynamic processes have opportunities as a degradable materials implant, but rolling is more recommended both in terms of mechanical properties and corrosion rates.

A Comonomer Strategy for Triggered Degradation and Re/Upcycling of High-Performance Thermoset Plastics

Thermosets play a key role in the modern plastics and rubber industries, comprising ~18% of polymeric materials with a worldwide annual production of 65 million tons. The high density of crosslinks that give these materials their useful properties comes at the expense of facile degradability and re/upcyclability. Here, using the high-performance industrial thermoset plastic poly-dicyclopentadiene (pDCPD) as a model system, we show that when a small number of cleavable bonds are selectively installed within the strands of thermoset plastics using a low-cost comonomer approach, the resulting materials display the same exceptional properties as the native material yet they can undergo triggered degradation to yield soluble, re/upcyclable products of controlled size and functionality. In contrast, installation of cleavable crosslinks, even at comparably high loadings, does not produce degradable materials. These findings shed new light on the topology of polymer networks, revealing cleavable bond location as a universal design principle for controlled thermoset degradation and re/upcycling.<br>