Growing environmental concern has led to an increase in the demand for ecofriendly coatings for paper. The use of renewable feedstock in place of synthetic raw materials is generating much interest in new scientific and technological developments. In this regard, we developed a biobased coating material using crosslinked alkyl chitosan with the objective to enhance the properties of kraft paper. Here, we used simple 1,4 conjugate addition between chitosan (Ch) and pentaerythritol triacrylate, followed by octadecyl amine (ODA), producing crosslinked ODA-grafted chitosan (Ch-ODA). The formation of Ch-ODA was confirmed by FT-IR and solid-state C-13 NMR spectroscopic studies. The dispersion of Ch-ODA was used for the dip-coating of kraft papers, and such coated kraft papers showed significant improvement in mechanical properties (tensile index: from 17.1 to 32.8 N m/g), hydrophobicity (water contact angle (WCA): from 81.5 degrees to 119.8 degrees), good tolerance to sandpaper abrasion (WCA: 112-139 degrees after 100 cycles), and adhesive tape peeling (WCA: 113 degrees-139 degrees after 10 cycles). The impact of the coating on the porosity of the kraft paper was analyzed by scanning electron microscopy. The coated kraft paper was found to be compostable in soil, and we explored its potential use in mulching.

Oxalate esters and isosorbide serve as intriguing polymer building blocks, as they can be sourced from renewable resources, such as CO2 and glucose, and the resulting polyesters offer outstanding material properties. However, the low reactivity of the secondary hydroxyl groups makes it difficult to generate high-molecular-weight polymers from isosorbide. Combining diaryl oxalates with isosorbide appears to be a promising approach to produce high-molecular-weight isosorbide-based polyoxalates (PISOX). This strategy seems to be scalable, has a short polymerization time (<5 h), and uniquely, there is no need for a catalyst. PISOX demonstrates outstanding thermal, mechanical, and barrier properties; its barrier to oxygen is 35 times better than PLA, it possesses mechanical properties comparable to high-performance thermoplastics, and the glass transition temperature of 167 degrees C can be modified by comonomer incorporation. What makes this high-performance material truly exceptional is that it decomposes into CO2 and biomass in just a few months in soil under home-composting conditions and it hydrolyzes without enzymes present in less than a year in 20 degrees C water. This unique combination of properties has the potential to be utilized in a range of applications, such as biomedical uses, water-resistant coatings, compostable plastic bags for gardening and agriculture, and packaging plastics with diminished environmental impact.