Wulfsohn      POLYONE CORPORATION68 Exhibit 31.1 CERTIFICATION I, Robert M. Richardson   POLYONE CORPORATION Exhibit 32.1 CERTIFICATION PURSUANT TO 18 U.S.C. POLYONE CORPORATION Exhibit 32.2 CERTIFICATION PURSUANT TO 18 U.S.C.

MSP SOLUTION Certificate of Analysis (COA) - labeled as "Material"

SUSTAINABILITY Avient’s color and additive manufacturing sites comply with ISO standards such as ISO 9001:2015 QMS, ISO 14001:2015 Environmental Management System and ISO 45001:2018*. EC) 1907/2006 and amendments) • UL94 file for MB (QMQS.E73454) and formulations (QMQS.E103015) • “Toys declaration” Directive 2009/48/EC • Waste Electrical & Electronic Equipment (WEEE) * Contact us for more detailed information about our ISO certifications.

Industrial Valle del Cinca s/n Apartado 18 22300 Barbastro, Huesca Spain has been assessed by ABS Quality Evaluations, Inc. and found to be in conformance with the requirements set forth by: ISO 14001:2015 The Environment Management System is applicable to: DEVELOPMENT, PRODUCTION & DISTRIBUTION OF TECHNICAL THERMOPLASTICS. This certificate may be found on the ABS QE Website (www.abs-qe.com). Validity of this certificate may be confirmed at www.abs-qe.com/cert_validation.

1 (3) Pending matter(s) The register indicates pending matter(s) regarding a change to the registered information at the time this certificate was created. 2 (3) Registration number: 516411-5031 Business name: Avient S.à r.l., Sweden Filial Address: Drottninggatan 56 411 07 GÖTEBORG County and municipality: Västra Götaland, Göteborg Note: MANAGING DIRECTOR 630516 Palm, Christoph, Gruss Strooss 35, L-9991 WEISWAMPACH, LUXEMBURG AUDITORS 556053-5873 Ernst & Young Aktiebolag, Box 7850, 103 99 STOCKHOLM Represented by: 850807-5135 PRINCIPALLY RESPONSIBLE AUDITOR 850807-5135 Edman, Mikael Thomas Gunnar, c/o Ernst & Young AB, 401 82 GÖTEBORG SIGNATORY POWER Signatory power alone by Palm, Christoph FINANCIAL YEAR Registered financial year: 0101 - 1231 DATE OF REGISTRATION OF CURRENT AND PREVIOUS BUSINESS NAMES 2021-11-29 Avient S.à r.l., Sweden Filial 2018-08-28 PolyOne S.à.r.l., Sweden Filial INFORMATION ABOUT THE FOREIGN COMPANY B226205 Avient S.á.r.l. 19, Route de Bastogne L-9638 Pommerloch LUXEMBURG Registered office of the foreign company: Pommerloch Name of the register in which the foreign company is registered: 3 (3) RCS, Registre de Commerce, Luxembourg Business Register LUXEMBURG Foreign company's financial year: 0101 - 1231 The above information is an extract from the Trade and Industry Register Bolagsverket, the Swedish Companies Registration Office.

质量管理体系认证认证 证书编号：04624Q15809R1S 兹证明: 法博莱恩纱线（常州）有限公司 统一社会信用代码：91320412MA1NMF5W4P 质量管理体系符合: GB/T 19001-2016 / ISO 9001:2015 标准 证书覆盖范围: 纺织品（纱线）、玻璃制品（纱线）的包覆加工 注册地址/实际地理地址：江苏省常州西太湖科技产业园兰香路 8 号研发车间 5 厂房 颁证日期：2024-10-26 有效期至：2027-10-25 初次颁证日期：2021-10-28 证书编号 受审核方 组织机构代码 认证范围 注册地址 生产办公地址 注册日期 有效期至 初次颁证日期 二维码

October 13, 2015 October 27, 2015 at 8:00 a.m. ET, October 27, 2015

Exhibit 31.1 CERTIFICATION I, Robert M. Patterson Exhibit 31.2 CERTIFICATION I, Bradley C. Exhibit 32.2 CERTIFICATION PURSUANT TO 18 U.S.C.

Employees 4 Sole shareholder Name Clariant Plastics & Coatings AG Visiting address Rothaustrasse 61, CH-4132 Muttenz 1, Switzerland Registered in Handelsregister Basel-Landschaft, Switzerland This extract has been certified with a digital signature and is an official proof of registration in the Business Register. The Chamber of Commerce recommends that this document be viewed in digital form so that its integrity is safeguarded and the signature remains verifiable. 20 21 -0 4- 12 1 4: 06 :2 8 under number CHE-112.279.714 Sole shareholder since 20-10-2015 (registration date: 03-11-2015) Board members Name Borst, Rainer Erich Date of birth 10-10-1961 Date of entry into office 01-07-2020 (registration date: 06-07-2020) Title Director Name Kamalak, Ihsan Date of birth 21-08-1985 Date of entry into office 01-07-2020 (registration date: 06-07-2020) Title Director Name Merklein, Norbert Date of birth 03-05-1964 Date of entry into office 05-03-2021 (registration date: 30-03-2021) Extract was made on 12-04-2021 at 14.06 hours. This extract has been certified with a digital signature and is an official proof of registration in the Business Register.

April 22, 2015 What: Wells Fargo 2015 Industrial and Construction Conference When: Wednesday, May 6, 2015 – Presentation Time: 2:35 PM