Researchers from the Kanazawa University in Japan publish a fine-tuned method to repurpose waste matter from the paper industry as a lightweight automotive structural material.
Given concerns over global climate warming, researchers are hard at work on minimizing the amount of fuel that we all use in everyday life. Reducing the weight of vehicles will lessen the amount of fuel required to power them and could potentially help reduce the harmful impact of manufacturing vehicles on the environment.
In a study published inChemical Engineering Journal, researchers from Kanazawa University have chemically modified an industrial waste product, and processed it into a possible lightweight structural material. This development may increase the fuel economy of private and commercial transportation.
The researchers started with Kraft lignin, a by-product of a common wood pulping process. Paper mills usually burn Kraft lignin to generate power. Chemically processing Kraft lignin into a more useful material would improve the environmental sustainability of paper production.
“We performed a chemical modification of Kraft lignin polymer known as acetylation. Optimizing the extent of acetylation was critical to our research effort,” said first author László Szabó.
A controlled reaction was important for optimizing Kraft lignin's ability to be compatible with another polymer called polyacrylonitrile, and thus prepare quality carbon fibres creating an engineered composite. Imbalance of the acetylation process could cause the carbon fibres to be of low quality.
“Our reaction was quite mild, producing only a rather benign side product--acetone--without changing the polydispersity of the Kraft lignin,” explained Kenji Takahashi, co-senior author. “We thus were able to mix Kraft lignin with polyacrylonitrile to obtain a dope solution for electrospinning containing more compatible polymer segments and eventually fabricate quality carbon fibres.”
The researchers' carbon fibre mats contain fine uniform fibres, without the thermal treatment reducing fibre quality. In fact, compared with unmodified Kraft lignin, by using the modified polymer the fibre mat exhibited an almost three-fold improvement in mechanical strength.
“Our fibres’ mechanical performance is attributable to the tailored graphitic structure of the materials,” said László Szabó. “This outcome is owing to the improved polymer interactions leading to a more aligned polymeric network which is then subjected to the thermal treatment.”
Engineered composites are commonly used many products and technologies such as spacecrafts, cars, plastic, and concrete. This discovery could potentially minimize the cost of preparing their new carbon fibres, and make lighter, more durable and fuel-efficient vehicles.