Exhibit 3.1

CERTIFICATE OF AMENDMENT

TO THE

RESTATED CERTIFICATE OF INCORPORATION

OF

ASPEN AEROGELS, INC.

Aspen Aerogels, Inc. (the “Corporation”), a corporation organized and existing under the laws of the State of Delaware, does hereby certify as follows:

FIRST: That the name of the Corporation is Aspen Aerogels, Inc.

SECOND: That the Board of Directors of the Corporation duly adopted resolutions approving the following amendment of the Restated Certificate of Incorporation, declaring said amendment to be advisable and providing for such consideration of such amendment at the Corporation’s annual meeting of the stockholders.

THIRD: On June 1, 2023 the Corporation’s annual meeting of the stockholders was duly called and held, upon notice in accordance with Section 222 of the General Corporation Law of the State of Delaware (“DGCL”), at which meeting the necessary number of shares as required by statute were voted in favor of the amendment.

FOURTH: Paragraph FOURTH, Section A. of the Restated Certificate of Incorporation be, and it hereby is, amended and restated in its entirety as follows:

A. Designation and Number of Shares.

The total number of shares of all classes of stock which the Corporation shall have the authority to issue is 255,000,000 shares, consisting of 250,000,000 shares of common stock, par value $0.00001 per share (the “Common Stock”) and 5,000,000 shares of preferred stock, par value $0.00001 per share (the “Preferred Stock”).

The number of authorized shares of Common Stock or Preferred Stock may be increased or decreased (but not below the number of shares thereof then outstanding) by the affirmative vote of the holders of a majority of the voting power of all of the then-outstanding shares of capital stock of the Corporation entitled to vote thereon, without a separate vote of the holders of the Common Stock or the Preferred Stock, respectively, or of any series thereof, unless a vote of any such holders is required pursuant to the terms of any Preferred Stock designation.

FIFTH: The Restated Certificate of Incorporation of the Corporation is hereby amended to add a new paragraph THIRTEENTH, to read in its entirety as follows:

THIRTEENTH: No officer shall be personally liable to the Corporation or its stockholders for any monetary damages for breaches of fiduciary duty as an officer; provided that this provision shall not eliminate or limit the liability of an officer, to the extent that such liability is imposed by applicable law, (i) for any breach of the officer’s duty of loyalty to the Corporation or its stockholders; (ii) for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law; (iii) under Section 174 or successor provisions of the Delaware General Corporation Law; (iv) for any transaction from which the officer derived an improper personal benefit, or (v) in any action by or in the right of the Corporation. No amendment to or repeal of this provision shall apply to or have any effect on the liability or alleged liability of any officer for or with respect to any acts or omissions of such officer occurring prior to such amendment or repeal. If the Delaware General Corporation Law is amended to authorize corporate action further eliminating or limiting the personal liability of officers, then the liability of an officer of the Corporation shall be eliminated or limited to the fullest extent permitted by the Delaware General Corporation Law, as so amended.

SIXTH: That this Certificate of Amendment to the Restated Certificate of Incorporation shall be effective at 4:00 p.m. Eastern Time on June 1, 2023.

IN WITNESS WHEREOF, this Certificate of Amendment to the Restated Certificate of Incorporation has been executed by a duly authorized officer of this Corporation on this 1st day of June, 2023

ASPEN AEROGELS, INC.
By:	/s/ Donald R. Young
Donald R. Young
President and Chief Executive Officer