Biomass solid wastes

such as lignin and collagen

are potentialized to be developed as coal tar pitch alternatives to prepare the carbon products. However

controlling the puffing behavior during the carbonization is a key factor to obtain the excellent carbon materials. In the present study

green composites using the pine softwood lignin and collagen as hybrid binder were prepared by the hot-pressing process. The effect of baking program and puffing inhibitors on the puffing behavior was evaluated. Elemental analysis and Scanning Electronic Microscopy (SEM) were also employed for further study. Results showed that a lower heating rate (baking rate of 0.04 ℃/min to 500 ℃

then 0.07 ℃/min to 500-800 ℃) and a higher cooling rate (1.08 ℃/min) were preferred for puffing inhibition. Some traditional puffing inhibitors

such as coconut shell

lignite coal feed

boric acid

ferric oxide

and iron (Ⅲ) chloride

were not available to the bio-binder system. Along with the improvement of puffing inhibition

the apparent density of the baked product gradually decreased. In the case of a mixture system containing ferric oxide

the rising temperature promoted the enrichment of carbon element and the decrease of other elements such as N

S

and O

resulting in fluctuating change in Fe content. The lignin/collagen hybrid system served as thermally-fused binder to form a new integrated char with turbostratic structure by means of covering

filling and bridging

and iron precipitates derived from ferric oxide was observed on the surface of char during the graphitization.