PolyOne sponsors various voluntary retirement savings plans (RSP). Exhibit 31.1 CERTIFICATION I, Robert M. Patterson Exhibit 31.2 CERTIFICATION I, Bradley C.

I look forward to sharing more details in our third quarter earnings call and at our upcoming investor day in The webcast can be viewed live at avient.com/investors, or by clicking on the webcast link here.  performance in prior periods without the effect of items that, by their nature, tend to obscure

I am extremely pleased with our record fourth quarter results, as every segment and end market grew over the prior year fourth quarter. The webcast can be viewed at avient.com/investors, or by clicking here: https://edge.media-server.com/mmc/p/ko4y5g9z. performance in prior periods without the effect of items that, by their nature, tend to obscure

 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 limitation, 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 and 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, changes in interest rates and changes in the rate of inflation Patterson 12:00-1:00 PM Lunch PolyOne Corporation Page 7 PolyOne Commodity to Specialty Transformation • Volume driven, commodity producer • Heavily tied to cyclical end markets • Performance largely dependent on non- controlling joint ventures 2000-2005 2006 - 2009 2010 – 2014 2015 and beyond • Steve Newlin appointed, Chairman, President and CEO • New leadership team appointed • Implementation of four pillar strategy • Focus on value based selling, investment in commercial resources and innovation to drive transformation • 18 consecutive quarters of double- digit adjusted EPS growth • Shift to faster growing, high margin, less cyclical end markets • Key acquisitions propel current and future growth, as well as margin expansion • Established aggressive 2015 targets • Continue specialty transformation • Targeting $2.50 adjusted EPS by 2015, nearly double 2013 EPS • Drive double digit operating income and adjusted EPS growth PolyOne Corporation Page 8 Specialty 54% PP&S Distribution 28% 2013 Revenues: $3.8 Billion 2013 Revenues: $3.8 Billion United States 67% Latin America $13 $31 $46 $46 $92 $96 $122 $195 $0 $50 $100 $150 $200 2006 2007 2008 2009 2010 2011 2012 2013 End Markets Specialty Operating Income PolyOne At a Glance Building & 9% HealthCare 11% Appliance Electronics & Electrical PolyOne Corporation Page 9 Old PolyOne Transformation *Operating Income excludes corporate charges and special items 2% 34% 43% 62% 64% 0% 20% 40% 60% 80% 100% 2005 2008 2010 2013 Q1 2014 2015 % o f O p e ra ti n g I n c o m e * JV's Performance Products & Solutions Distribution Specialty 65-75% Specialty OI $5M $46M $87M $195M $60M Target Mix Shift Highlights Specialty Transformation 2015 Target PolyOne Corporation Page 10 Confirmation of Our Strategy The World’s Premier Provider of Specialized Polymer Materials, Services and Solutions Specialization Globalization Operational Excellence Commercial Excellence PolyOne Corporation Page 11 -150.00% -50.00% 50.00% 150.00% 250.00% 350.00% 450.00% 550.00% PolyOne S&P 500 Strategy and Execution Drive Results $0.12 $0.27 $0.21 $0.13 $0.68 $0.82 $1.00 $1.31 '06 '07 '08 '09 '10 '11 '12 '13 ‘06-‘13 EPS CAGR = 41% EPS Share Price vs.  Strong past performance demonstrates that our strategy and execution are working  Megatrends and emerging opportunities align with our strengths  Innovation and services provide differentiation, incremental pricing power, and competitive advantage  Strong and proven management team driving growth and performance  Addressable market exceeds $40 billion PolyOne Corporation Page 44 Appendix Kiosk Summaries Segments at a Glance Officer Biographies PolyOne Corporation Page 45 Anti-Counterfeiting Solutions  Includes formulation and consultative services to assist manufacturers and brand owners in positively identifying their packaging, devices, end products and raw materials in the field  Protects brand equity – defense against customer complaints or legal actions based on erroneous product identification  Protects consumer welfare – decrease in potential harm to consumers, reduction in unwarranted recall expenses  Secures supply chain integrity – support for safe expansion into new geographies PolyOne Corporation Page 46 Security and Safety Solutions  Polycast™ Bullet Resistant Sheet, an optically clear, non-yellowing acrylic, provides ballistics protection against powerful weapons • High-impact resistance that foils “smash-and-grab” thieves  GlasArmor™ Bullet Resistant Panels, a UL-listed solution with superior ballistic resistance yet weights 75% less than steel panel • Used in commercial security applications for business, home, and governmental facilities PolyOne Corporation Page 47 3D Printing  Collaborating with customers using 3D printers to create prototypes and samples  Enables customers to develop and test their products and innovations quickly and accurately  3D printing of molds and inserts allows OEMs to develop and test new product innovation using their own equipment and material of choice, more efficient than traditional processes PolyOne Corporation Page 48 Enhanced Ergonomic Technologies  Versaflex™ VDT was developed to absorb vibration and noise in a broad range of applications, including minimally invasive surgical instruments, electronics, firearms, archery and automotive  Can be overmolded onto a rigid substrate without the need for an adhesive to increase production efficiencies and profitability  Creates value by: • Increasing end-user comfort • Eliminating secondary assembly • Differentiating end products PolyOne Corporation Page 49 Sustainable Solutions  reFlex™ Bio-Based Plasticizer non- phthalate additive used to make vinyl more flexible • Derived primarily from soybeans rather than petroleum • Certified by USDA BioPreferred® program  Wilflex™ Oasis Water-Based Inks satisfy consumer demand for eco- conscious products • Long screen life and production- friendly to improve operational efficiencies, increase design quality PolyOne Corporation Page 50 Color and Design Services  First-of-its-kind offering that supports color and product development from concept to reality  Helps brand managers and designers evaluate color and design alternatives to: – accelerate and streamline product development – strengthen brand equity – build marketplace excitement  Enhances product differentiation  Improves efficiency and profitability PolyOne Corporation Page 51 Metal Replacement Technology  Portfolio of solutions that meet upper range of performance requirements, removing barriers to replacing metal with polymers  Applications include: • LED heat sinks • Electronic shielding (EMI/RFI) • Structural integrity at elevated temperatures (i.e., large appliances) • Lead-free radiation shielding (i.e., CT scanners)  Creates value by eliminating the need for machining and secondary operations, removing weight, streamlining production and improving cost efficiencies PolyOne Corporation Page 52 Medical Device Solutions  Catheters made using NEU™ View patent-pending technology are optically translucent, and have superior contrast under X-ray (radiopaque) when compared with alternative catheter materials  Formulations for cardiovascular and intravascular catheters are application-specific, incorporating medical-grade polymers, additives, color, and healthcare-centric manufacturing practices  Only commercially available product that has excellent visibility, both optically and under X-ray, to bolster clinician confidence and offer significant market advantage PolyOne Corporation Page 53 Consumer Electronics Solutions  Ability to offer multiple technology solutions on a global basis for this industry, where many OEMs design in one region, prototype in another, and manufacture in yet another  Sustainable / “green” solutions help customers to differentiate in this market  New formulations for emerging wearables market that meet skin contact requirements and aesthetic needs PolyOne Corporation Page 54 Building & 17% Electrical & 8% 19% At a Glance Global Specialty Engineered Materials 2013 Revenues: $0.6 Billion Solutions 2013 Revenue by Industry Segment Expanding Profits 1.1% 1.3% 3.4% 5.1% 9.6% 8.0% 8.6% 9.3% 12-16% 2006 2007 2008 2009 2010 2011 2012 2013 Q1 2014 2015 Operating Income % of Sales Target 43% 33% 11.6% PolyOne Corporation Page 55 Building & Electrical & Target At a Glance Global Color, Additives and Inks 2013 Revenues: $0.9 Billion Solutions Expanding Profits 1.7% 4.6% 5.1% 5.5% 7.2% 8.1% 9.7% 12.2% 12-16% 2006 2007 2008 2009 2010 2011 2012 2013 Q1 2014 2015 Operating Income % of Sales 44% 37% 2013 Revenue by Industry Segment 13.8% PolyOne Corporation Page 56 At a Glance Designed Structures and Solutions Solutions 2013 Revenues: $0.6 Billion Expanding Profits 2.2% 8 - 10% 6.5% 2012 PF Q1 2013 Q1 2014 2015 Operating Income % of Sales 0.2% Target 96% 1% Building & 32% 26% 2013 Revenue by Industry Segment PolyOne Corporation Page 57 5.5% 6.9% 3.8% 3.6% 5.5% 4.3% 6.3% 7.2% 2006 2007 2008 2009 2010 2011 2012 2013 Q1 2014 Operating Income % of Sales At a Glance Performance Products and Solutions Solutions Expanding Profits 2013 Revenues: $0.8 Billion 81% 1% 9-12% Target 2013 Revenue by Industry Segment 8% Building & 4% Electrical & 1%Industrial 2015 7.7% PolyOne Corporation Page 58 2.6% 3.0% 3.5% 4.0% 4.6% 5.6% 6.4% 5.9% 6 - 7.5% 2006 2007 2008 2009 2010 2011 2012 2013 Q1 2014 2015 Operating Income % of Sales 15.3% 46.0% 2006 Q1 2014 At a Glance Distribution *ROIC is defined as TTM adjusted OI divided by the sum of average debt and equity over a 5 quarter period Solutions 2013 Revenues: $1.1 Billion ROIC* Expanding Profits Target Building & Electrical & 24% 23% 6.1% http://www.avient.com/Pages/VariationRoot.aspx

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 limitation, 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 and 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, changes in interest rates and changes in the rate of inflation. • The above list of factors is not exhaustive. • We undertake no obligation to publicly update forward-looking statements, whether as a result of new information, future events or otherwise. Strong past performance demonstrates that our strategy and execution are working • Megatrends align with our strengths • Innovation and services provide differentiation and competitive advantage • Strong and proven management team driving growth and performance • Addressable market exceeds $40 billion The New PolyOne: A Specialty Growth Company 2015 Target: $2.50 Adjusted EPS Page 15 Schedule I Reconciliation of Non-GAAP Financial Measures (Unaudited) (Dollars in millions, except per share data) Below is a reconciliation of non-GAAP financial measures to the most directly comparable measures calculated and presented in accordance with U.S.

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 limitation, 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 and 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, changes in interest rates and changes in the rate of inflation. • The above list of factors is not exhaustive. • We undertake no obligation to publicly update forward-looking statements, whether as a result of new information, future events or otherwise. Strong past performance demonstrates that our strategy and execution are working • Megatrends align with our strengths • Innovation and services provide differentiation and competitive advantage • Strong and proven management team driving growth and performance • Addressable market exceeds $40 billion The New PolyOne: A Specialty Growth Company 2015 Target: $2.50 Adjusted EPS Page 15 Schedule I Reconciliation of Non-GAAP Financial Measures (Unaudited) (Dollars in millions, except per share data) Below is a reconciliation of non-GAAP financial measures to the most directly comparable measures calculated and presented in accordance with U.S.

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 limitation, 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 and 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, changes in interest rates and changes in the rate of inflation. • The above list of factors is not exhaustive. • We undertake no obligation to publicly update forward-looking statements, whether as a result of new information, future events or otherwise. Strong past performance demonstrates that our strategy and execution are working • Megatrends align with our strengths • Innovation and services provide differentiation and competitive advantage • Strong and proven management team driving growth and performance • Addressable market exceeds $40 billion The New PolyOne: A Specialty Growth Company 2015 Target: $2.50 Adjusted EPS Page 14 Schedule I Reconciliation of Non-GAAP Financial Measures (Unaudited) (Dollars in millions, except per share data) Below is a reconciliation of non-GAAP financial measures to the most directly comparable measures calculated and presented in accordance with U.S.

You can identify these statements by the fact that they do not relate strictly to historic or current facts. All Rights Reserved 2025 Avient 2024 sales B U S I N E S S S E G M E N T S E N D M A R K E T S R E G I O N S 63% 37% S E M C A I 23% 20% 15% 10% 10% 8% 7% 4% 3% Packaging Telecom Energy Defense Healthcare Building & construction Transportation Industrial Consumer 41% 35% 18% 6% US & Canada Latin America Asia Europe, Middle East and Africa 14Copyright © . All Rights Reserved 2025 16 Avient 2024 regional sales, by end market U S & C AN AD A 41% of sales E M E A 35% of sales AS I A 18% of sales L AT I N AM E R I C A 6% of sales 13% 22% 14% 9% 13% 10% 9% 6% 4% Packaging TelecomEnergyDefenseHealthcareBuilding & construction TransportationIndustrialConsumer 26% 13% 16% 13% 10% 5% 10% 5% 2% 31% 26% 14% 10% 5% 10% 1% 1% 2% 61% 20% 7% 6% 4% 2% Copyright © .

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Avient Launches Medical TPE Grades Formulated Without Animal Derivatives