No. 0962.01) 09/05/2023 Page 1 of 1 SCOPE OF ACCREDITATION TO ISO/IEC 17025:2017 AVIENT CORPORATION 80 North West Street Norwalk, OH 44857 Craig Polta Phone: 419 660 4278 MECHANICAL Valid To: 2025年9月30日 Certificate Number: 0962.01 In recognition of the successful completion of the A2LA evaluation process, accreditation is granted to this laboratory to perform the following tests on plastics: Test Method(s) Test Name ASTM D256; ISO 180 Notched Izod ISO 179 (1eA) Determination of Charpy Impact ASTM D523 Gloss ASTM D618 (Method A) Conditioning of Test Specimens ASTM D792 (Method A) Specific Gravity ASTM D1238 (Method B) Melt Flow Rate ASTM D3012 Thermal Oxidative Stability ASTM D3641 Injection Molding Test Specimens FMVSS 302 Flammability ASTM E1331; SAE J1545 Spectrophotometric Color Difference SAE J1885 (Rev. MAR2005)1, J2412, J2527; BO 116-01 Xenon Arc Weathering (Exposure Testing) SAE J361 Visual Inspection of Automotive Trim GM9302P, GMW17141 Stress Mark Susceptibility GMW14688 Scratch and Mar Resistance (Erichsen) BN108-13, BO162-01 Resistance to Scratching GMW3205 Resistance to Odor Propagation of Interior Materials 1 This laboratory’s scope contains a superseded method. Accredited Laboratory A2LA has accredited AVIENT CORPORATION Norwalk, OH for technical competence in the field of Mechanical Testing This laboratory is accredited in accordance with the recognized International Standard ISO/IEC 17025:2017 General requirements for the competence of testing and calibration laboratories.

Slide 1 PolyOne Corporation Page 1 PolyOne Investor Presentation Bank of America Merrill Lynch 2014 US Basic Materials Conference Boston, MA 2014年12月11日 PolyOne Corporation Page 2 Forward-Looking Statements  In this presentation, statements that are not reported financial results or other historical information are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. They are based on management’s expectations that involve a number of business risks and uncertainties, any of which could cause actual results to differ materially from those expressed in or implied by the forward-looking statements. Appendix Q3 2014 Financial Highlights At a Glance�Global Color, Additives and Inks At a Glance�Global Specialty Engineered Materials At a Glance�Designed Structures and Solutions At a Glance�Performance Products and Solutions At a Glance�Distribution Plastics: Key to Future Sustainable Development Commitment to Operational Excellence Application Examples Slide Number 28 Anti-Counterfeiting Solutions 2012 Range Rover Evoque Interior Slide Number 31 Metal Replacement Solutions Next Generation Solar Charger High-Barrier Packaging Containers Aerospace Applications Non GAAP Rec - 11 5 14.pdf Sidoti & Company non-GAAP Rec

Avient’s chief operating decision maker uses these financial measures to monitor and evaluate the ongoing performance of Avient and each business segment and to allocate resources. Each of such adjustments has not yet occurred, are out of Avient’s control and/or cannot be reasonably predicted. Senior management believes the measures described above are useful to investors because they allow for comparison to Avient's performance in prior periods without the effect of items that, by their nature, tend to obscure Avient's operating results due to the potential variability across periods based on timing, frequency and magnitude.

Avient Corporation. Avient Corporation. All Rights Reserved 2025 27 NON-HYDROCARBON MATERIALS HYDROCARBON-BASED ~35% of the raw material basket including part of “Other raw materials” are hydrocarbon-based Raw material basket 16% 14% 9% 2% 37% 9% 5% 4% 4% Performance additives Pigments TiO2 Dyestuffs Styrenic block copolymers Polypropylene Nylon Polyethylene Other raw materials Reconciliation of Non-GAAP Financial Measures (Unaudited) (Dollars in millions, except for per share data) Senior management uses comparisons of adjusted net income from continuing operations attributable to Avient shareholders and diluted adjusted earnings per share (EPS) from continuing operations attributable to Avient shareholders, excluding special items, to assess performance and facilitate comparability of results.

Slide 1 PolyOne Corporation Page 1 PolyOne Investor Presentation Credit Suisse Basic Materials Conference June 25-26, 2014 PolyOne Corporation Page 2 Forward-Looking Statements  In this presentation, statements that are not reported financial results or other historical information are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. They are based on management’s expectations that involve a number of business risks and un certainties, any of which could cause actual results to differ materially from those expressed in or implied by the forward-looking statements.  Factors that could cause actual results to differ materially from those implied by these forward-looking statements include, but are not limited to:  The final amount of charges resulting from the planned North American asset realignment and the Company’s ability to realize anticipated savings and operational benefits from the asset realignment;  Our ability to achieve the strategic and other objectives relating to the acquisition of Spartech Corporation, including any expected synergies;  Our ability to successfully integrate Spartech and achieve the expected results of the acquisition, including, without limita tion, the acquisition being accretive;  Disruptions, uncertainty or volatility in the credit markets that could adversely impact the availability of credit already arranged and the availability and cost of credit in the future;  The financial condition of our customers, including the ability of customers (especially those that may be highly leveraged a nd those with inadequate liquidity) to maintain their credit availability;  The speed and extent of an economic recovery, including the recovery of the housing market;  Our ability to achieve new business gains;  The effect on foreign operations of currency fluctuations, tariffs, and other political, economic and regulatory risks;  Changes in polymer consumption growth rates in the markets where we conduct business;  Changes in global industry capacity or in the rate at which anticipated changes in industry capacity come online;  Fluctuations in raw material prices, quality and supply and in energy prices and supply;  Production outages or material costs associated with scheduled or unscheduled maintenance programs;  Unanticipated developments that could occur with respect to contingencies such as litigation and environmental matters;  An inability to achieve or delays in achieving or achievement of less than the anticipated financial benefit from initiatives related to working capital reductions, cost reductions, employee productivity goals, and an inability to raise or sustain prices for products or services;  An inability to raise or sustain prices for products or services;  An inability to maintain appropriate relations with unions and employees;  The inability to achieve expected results from our acquisition activities;  Our ability to continue to pay cash dividends;  The amount and timing of repurchases of our common shares, if any; and  Other factors affecting our business beyond our control, including, without limitation, changes in the general economy, chang es in interest rates and changes in the rate of inflation

ABS Quality Evaluations This is to certify that the Environmental Management System of: Avient Corporation Avient Corporation HQ 33587 Walker Road Avon Lake, OH 44012 U.S.A. Ezcabarte calle H Nº3 Oricain, Navarra 31194 Spain Facility: Avient Corporation - Phan Thong 700/848 Moo 1,Tambol Phan Thong Amata City Chonburi Industrial Estate Phan Thong, Chonburi 20160 Thailand Activity: Manufacture of Masterbatches, Additives, ECCOH, and Compounds for Pigmenting Thermoplastic Activity: Design and Manufacture of Colorants and Additives for Plastics Facility: Avient Corporation - Pogliano, Italy Via Lainate 26 20005, Pogliano Milanese, Milano Italy Facility: Avient Corporation - Randburg, South Africa 329 Tungsten Rd, Strydompark Randburg, Gauteng 2194 South Africa Activity: Manufacture of Colour and Additive Concentrates, Thermoplastic Resins and Specialty Compounds Activity: Manufacture of Masterbatches Facility: NEU Specialty Engineered Materials, LLC 15 Corporate Drive North Haven, CT 06473 U.S.A. Activity: Design and Manufacture of Plastics Compounding Material and Thermoplastic Elastomers Page 10 of 10 ABS Quality Evaluations Avient Corporation ISO 14001:2015 Certificate Of Conformance ANNEX At Below Facilities: Validity of this certificate may be confirmed at www.abs-qe.com/cert_validation.

ABS Quality Evaluations This is to confirm that the Environmental, Health, Safety and Security Management System of: Avient Corporation Avient Corporation HQ 33587 Walker Road Avon Lake, OH 44012 U.S.A. Ezcabarte calle H Nº3 Oricain, Navarra 31194 Spain Facility: Avient Corporation - Phan Thong 700/848 Moo 1,Tambol Phan Thong Amata City Chonburi Industrial Estate Phan Thong, Chonburi 20160 Thailand Activity: Manufacture of Masterbatches, Additives, ECCOH, and Compounds for Pigmenting Thermoplastic Activity: Design and Manufacture of Colorants and Additives for Plastics Facility: Avient Corporation - Pogliano, Italy Via Lainate 26 20005, Pogliano Milanese, Milano Italy Facility: Avient Corporation - Randburg, South Africa 329 Tungsten Rd, Strydompark Randburg, Gauteng 2194 South Africa Activity: Design and Manufacture of Colour and Additive Concentrates, Thermoplastic Resins and Specialty Compounds Activity: Manufacture of Masterbatches Facility: NEU Specialty Engineered Materials, LLC 15 Corporate Drive North Haven, CT 06473 U.S.A. Activity: Design and Manufacture of Plastics Compounding Material and Thermoplastic Elastomers Page 10 of 10 ABS Quality Evaluations Avient Corporation RC14001®:2015 Certificate Of Conformance ANNEX At Below Facilities: Validity of this certificate may be confirmed at www.abs-qe.com/cert_validation.

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