• PDF / 1,290,357 Bytes
• 11 Pages / 584.957 x 782.986 pts Page_size
• 31 Downloads / 227 Views

DOWNLOAD

REPORT

---

porous carbon monoliths with different pore structures were obtained by carbonizing cured phenol–formaldehyde (PF) resin/poly(methyl methacrylate) (PMMA) blends. The effect of the molecular weight of PMMA, reaction activity of PF, and content ratio of compositions on the pore structure of carbon monoliths was systematically investigated, with emphasis on controlling the morphology of the nanostructure and pore size distribution. Nanostructures were an important factor in determining the compressive strength of porous carbon monoliths. The relationship between the nanoporous structure of carbon monoliths and compressive strength was revealed. Co-continuous pores provided escape channels for those volatile gases produced in the carbonization process to escape, reducing inner stress of the carbon materials. During compressive loading, co-continuous pores could also help to scatter and absorb the stress and energy. Porous carbon monoliths with a compressive strength of 34 MPa were obtained, and the compressive strength increased by 580% compared with that of carbon monoliths obtained from pure PF.

Contributing Editor: Paolo Colombo Address all correspondence to these authors. a) e-mail: [email protected] b) e-mail: [email protected] DOI: 10.1557/jmr.2015.331

strength.15,16 Liu and his coworkers17 prepared activated carbon honeycomb monoliths. The cold crushing strength was around 15 MPa. Soon later, homogeneous and crack-free porous carbon monoliths were prepared through a self-assembly of poly(benzoxazine-co-resol) and a carbonization process, whose compressive strength could reach 15.6 MPa.18 However, these methods are time-consuming and the mechanical strength of these nanoporous monolithic carbons is still relatively poor. A polymer blend method was a cost effective strategy to prepare carbons with a controlled pore structure and size. Yamazaki and coworkers found that,19 starting from miscible blends of phenol–formaldehyde resin (PF) and other polymers, nanostructured carbon with continuous pores was obtained. They investigated phase separation morphology which is formed from the PF/poly(methyl methacrylate) (PMMA) miscible blends. However, the effect of the PMMA content and type on the morphologies of porous carbon materials and the relationship between the nanostructure and mechanical strength have not been studied. In our work, PF/PMMA blends were used as the precursor to fabricate porous carbon monoliths by curing and carbonization. The effect of the molecular weight of PMMA, reaction activity of PF, and content ratio of the compositions on the carbon structure was studied. And the relationship between the morphology of nanopores and compressive strength of carbonaceous monoliths was systematically investigated.

3412

Ó Materials Research Society 2015

I. INTRODUCTION

Porous carbon materials, especially those containing nanopores, are widely used in many fields of science and technology, including catalysis,1,2 air separation,3 energy storage,4 double-layer capacitors,5 and preparation of structural carbide