1. Nanofibrillated cellulose (NFC) modified paper and softwood paper were used to prepare insulation papers with different structures, such as PPP, NNN, NPN and PNP.
2. The mechanical and electrical properties of the insulation papers were measured, including tensile strength, DC conductivity, dielectric response, space charge and breakdown strength.
3. A sandwich structure was used to regulate the mechanical and breakdown performance of the insulation paper, resulting in improved tensile strength and breakdown strength for oil-impregnated N/P/N paper.
The article is generally trustworthy and reliable due to its use of scientific evidence to support its claims. The article provides a detailed description of the materials used in the experiment as well as the methods employed to measure their properties. Furthermore, it cites relevant research studies that have been conducted in this field previously.
However, there are some potential biases that should be noted. For example, the article does not explore any counterarguments or alternative perspectives on the topic at hand. Additionally, it does not provide any information about possible risks associated with using nanofibrillated cellulose for insulation papers or any other potential drawbacks that could arise from this method. Finally, while it does cite previous research studies related to this topic, it does not provide an exhaustive list of all relevant literature in this field which could lead to a one-sided reporting of the issue at hand.