Exhibit 31.1 CERTIFICATION I, Stephen D. Newlin Exhibit 31.2 CERTIFICATION I, Robert M. Exhibit 32.2 CERTIFICATION PURSUANT TO 18 U.S.C.

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

Where it makes sense, we have gone beyond basic legal requirements, such as Responsible Care certification and implementation of the Product Safety Code. Through this data, we create safety data sheets, customer certification statements for appropriate use and product safety improvements. Combined, these facilities have a total of 205 certifications to an ISO or Management System and standards.

Seller warrants good and clear title in goods subject to the sale (“Product”) and that the Product con- forms at the time of shipment to a Certificate of Analysis, a Cer- tificate of Compliance, or a Product Specification Sheet, if any such document exists, and other specifications signed by Seller (“Specifications”). Säljaren garanterar att de produkter som är föremål för försäljningen (”Produkten”) är fria från rättsliga fel och att Produkten vid leveranstidpunkten stämmer överens med ett så kallat ”Certificate of Analysis”, ett ”Certificate of Compliance” eller ett ”Product Specification Sheet”, om något sådant existerar, och med andra specifikationer undertecknade av Säljaren (”Specifikationer”).

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.

Exhibit 31.1 CERTIFICATION I, Stephen D. Newlin Exhibit 31.2 CERTIFICATION I, Richard J. Exhibit 32.1 CERTIFICATION PURSUANT TO 18 U.S.C.

Global Compact & fulfilled Communication of Progress (COP) requirements • New Sustainability Strategy overview page including our 2022 AIP ESG metrics • New ESG Performance page with ESG ratings, awards, and certifications • Increased disclosures on carbon emissions, including disclosure of Climate Change Scenario Analysis • Added new Product Stewardship and Chemical Management policies • Enhanced data reporting for Workforce Demographics • Improved social disclosures on human rights, dependent care and special leave and strategic training management 2021 SUSTAINABILITY REPORT Launching integrated sustainability website in parallel with report Aligned with leading reporting frameworks 9 ESG PERFORMANCE & AWARDS 10 84th ENVIRONMENTAL SOCIAL GOVERNANCE 1 3 (as of 6/30/22) 2022 O U TLO O K $429 $490 $3.05 $3.50 FY 2022 GUIDANCE (TOTAL COMPANY: CURRENT PORTFOLIO) 12 Sales Adjusted Operating Income $4,819 $5,100 + 6% Adjusted EPS + 14% + 15% (in millions) (in millions) (+ 9% excluding FX) (+ 18% excluding FX) (+ 20% excluding FX) 13 CASH FLOW / LEVERAGE ($ millions) 2022E Cash Flow from Operating Activities 400$ Less: Run-Rate CapEx (90) CapEx for Clariant Integration (10) CapEx for IT System Upgrade (15) Total CapEx (115) Free Cash Flow 285$ Adjusted EBITDA 635$ Net Debt / Adjusted EBITDA 1.6x 14 DYNEEMA / DISTRIBUTION UPDATES • Strong performance so far in 2022 in-line with our modeling • Acquisition to be finalized as early as September 1, pending standard regulatory process and closing conditions • Encouraging interest thus far from potential buyers for world-class business with a strong track record • Second round bids due in August DISTRIBUTION 15 PRO FORMA MODELING UPDATE 2022E ($M) Revenue 5,100$ 415$ 5,515$ (1,635)$ 3,880$ Adjusted EBITDA 635 130 765 (109) 656 EBITDA % 12% 31% 14% 7% 17% Adj.

Global Compact • Highlights ESG Performance, including ratings, awards, and certifications • Features increased carbon emissions disclosures, including Climate Change Scenario Analysis and Scope 3 emissions data • Outlines Sustainable Supplier Program, designed to enable supplier evaluation & collaboration • Reflects Great Place To Work® culture focused on safety, employee engagement and advancing diversity, equity and inclusion 2022 SUSTAINABILITY REPORT 19 Avient Confidential 20 • Virtual presentation to be held September 20, 2023 • Leadership will be conducting an investor-focused presentation around our sustainable solutions portfolio • Deep dive into how we enable customers to achieve their sustainability goals SUSTAINABILITY DAY 20 …are Growing at Twice the Rate as Conventional Products Sustainably-Branded Products… STAKEHOLDER INFLUENCE DRIVES DEMAND Consumers Are demanding recyclability and eco- conscious products Governments Are mandating changes through legislation, taxes, and regional accords Brand Owners Have committed to ambitious goals to achieve sustainability metrics 21 AP P EN D IX 24 Performance Additives 16% Pigments 12% TiO2 Dyestuffs 2% Polyethylene Nylon Polypropylene Styrenic Block Copolymer Other Raw Materials 33% ~40% hydrocarbon based (Grey shaded materials are hydrocarbon based, includes portion of “Other Raw Materials”) Non-hydrocarbon based materials 2022 pro forma results for the acquisition of Avient Protective Materials RAW MATERIAL BASKET PEER COMPARISONS AVIENT IS ASSET LIGHT Capex / Revenue 2023E (%) Avient Specialty Other Specialty / Note: Avient reflects 2023 estimated revenue of $3,280 and estimated run-rate CAPEX of $110M. 26 3 3 4 4 4 5 5 7 7 9 10 FREE CASH FLOW CONVERSION Note: Free cash flow conversion calculated as (Adjusted EBITDA – Capex) / Adjusted EBITDA.

FX +4.6% FX -1.5% Total Avient +3.1% Note: Regional Sales Percentages exclude impact of foreign exchange Q2 2024 SEGMENT PERFORMANCE (COLOR, ADDITIVES & INKS) $525 $542 $94 $108 19.9% (in millions) (in millions) 10 17.9% +200 bps * Adjusted EBITDA Margin % • Organic sales growth in all regions led by Americas • Raw material deflation combined with cost reduction actions drove EBITDA margin expansion + 3% (+5% excluding FX) + 15% (+17% excluding FX) Q2 2024 SEGMENT PERFORMANCE (SPECIALTY ENGINEERED MATERIALS) $301 $308 $60 $64 20.6% (in millions) (in millions) 11 19.8% +80 bps * Adjusted EBITDA Margin % • Sales growth in consumer, healthcare and building & construction end markets offset by weaker demand in telecommunications • EBITDA margin expansion driven by positive end market mix as well as raw material deflation + 2% (+4% excluding FX) + 7% (+8% excluding FX) 2024 G U IDA N CE FY 2024 GUIDANCE Previous (May 7) Current Adjusted EBITDA $510 to $535 million $515 to $540 million Adjusted EPS $2.50 to $2.65 $2.55 to $2.70 Interest Expense $105 million $105 million Adjusted Effective Tax Rate 23% to 25% 23% to 25% Capital Expenditures ~$140 million ~$140 million 13 Q3 2024: Adjusted EPS of $0.62 14 Highlights • Provides performance updates on 2030 Sustainability Goals • Reduced company’s Scope 1 & 2 GHG emissions by 48% since 2019 • Highlights ESG performance ratings, certifications, and awards, including recent upgrades by Ecovadis to Gold and CDP to A- • Reflects Great Place to Work® culture focused on health, safety and employee engagement 2023 SUSTAINABILITY REPORT 14 Sustainability for a Better Tomorrow 2023 SUSTAINABILITY REPORT 15 • Investor Day to be held December 4, 2024 in New York, NY • The focus will be to do a deep dive on the Company’s strategy • Further details to be communicated 2024 AVIENT INVESTOR DAY AP P EN D IX 18 Performance Additives 15% Pigments TiO2 Dyestuffs Polyethylene 10%Nylon Polypropylene Styrenic Block Copolymer Other Raw Materials 38% ~40% hydrocarbon based (Grey shaded materials are hydrocarbon based, includes portion of “Other Raw Materials”) Non-hydrocarbon based materials RAW MATERIAL BASKET SEGMENT DATA U.S. & Canada 41% 2023 SEGMENT, END MARKET AND GEOGRAPHY GEOGRAPHY REVENUESEGMENT FINANCIALS 19% 23%Industrial Building and END MARKET REVENUE $2,007M $358M $1,138M $224M Sales EBITDA Specialty Engineered Materials Color Additives and Inks $502M$3,143M (1) 20 (1) Total company sales and adjusted EBITDA of $3,143M and $502M, respectively, include intercompany sales eliminations and corporate costs 2023 REVENUE | $2 .0 B ILL ION 34% 37% 21% END MARKET REGION 21 34% 21% 15% Building & 1% Energy COLOR, ADDITIVES & INKS 2023 REVENUE | $1 .1 B ILL ION 52% 35% 22 6%Industrial 12% 10% Defense Building & END MARKET REGION SPECIALTY ENGINEERED MATERIALS 32% 26% Building & 6% 2% Defense 1% (18% of sales) 2023 AVIENT REGIONAL SALES 25% Building & (36% of sales)Transportation 22% Building & 12% 6% US & Canada (41% of sales) 59% 22% Building & LATAM (5% of sales) 23 BY END MARKET 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.

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