Aspen Aerogels has filed for an IPO. The number of shares that will be sold as well as the stock’s pricing terms have yet to be set. Aspen Aerogels plans on listing the stock on the NYSE under the ticker symbol “ASPN.” Barclays Capital, J.P. Morgan Securities and Citigroup Global Markets are serving as lead underwriters. Headquartered in Northborough, Mass., Aspen Aerogels is a maker of aerogel insulation used mostly in energy infrastructure facilities. The firm’s backers include BASF Venture Capital, Reservoir Capital Partners, Arcapita Ventures, Tenaya Capital and RockPort Capital Partners.