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Technical articles on plastic and polymer failure, forensic testing, and expert-witness practice.
5 min read
Product DesignWhich Window Should I Use, Glass or Plastic?
Dr. Duane Priddy Sr. · October 8, 2024
This white paper reviews polycarbonate vs. glass pros & cons in exterior outdoor applications. Polycarbonate offers superior impact resistance and lightweight properties.
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4 min read
Pipe FailureWHY ARE PLASTIC PIPES FAILING IN HAWAII?
Dr. Duane Priddy Sr. · April 14, 2024
Plastic pipes for fire sprinklers or potable water in Hawaii condos and hotels are prone to degradation or installation errors.
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8 min read
Pipe FailurePolybutylene (PB) Pipes: Unveiling Three Critical Features Affecting Reliability
Dr. Duane Priddy Sr. · October 10, 2023
This white paper reviews the 3 common causes of Polybutylene tubing or pipe failures. Limitations include oxidative stability, crystallization behavior, and its polymorphic nature. This article aims to provide insight into the ongoing debate surrounding the use of Polybutylene pipes in potable water distribution systems.
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8 min read
Pipe FailureWhat do PP Pipes and PP Mesh Implants have in Common?
Dr. Duane Priddy Sr. · September 20, 2023
We at Plastic Expert Group are highly experienced in determining the cause of failure of all plastic parts having analyzed and tested thousands of plastic pipes including ABS, CPVC, HDPE, PEX, PP-R, and PVC pipes.
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3 min read
Pipe FailureWhy Are My Plastic Parts Failing at Weld Lines?
Dr. Duane Priddy Sr. · February 15, 2023
There are several types of fittings used to assemble a system of PEX pipes, these are the potential problems with using expansion fittings.
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2 min read
Product DesignHow Do I Choose The Right Plastic For My Part?
Dr. Duane Priddy Sr. · September 15, 2022
Choosing the right material and mold design for optimized mold flow and ultimate part strength is critical.
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3 min read
Pipe FailureHow Can I Determine If The CPVC Fire Sprinkler Piping Was Installed Properly?
Dr. Duane Priddy Sr. · September 15, 2022
Fire Marshals inspect fire sprinkler piping systems by looking at submittals and the exterior of the piping. The inside of the piping system is not inspected.
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2 min read
Product DesignWhy Are My Injection Molded Parts Failing?
Dr. Duane Priddy Sr. · September 15, 2022
Most failures of injection molded plastic parts are caused by either improper design of the part or improper design of the mold.
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1 min read
Consumer ProductsPlastic Skylight Breaking Causing Injury
Dr. Duane Priddy Sr. · September 15, 2022
Unless plastics are properly stabilized against UV degradation, the plastic becomes brittle and will break.
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2 min read
Plastic FundamentalsWhat Can Dissolve Plastic?
Dr. Duane Priddy Sr. · July 15, 2022
Most plastics degrade by oxidation when exposed to sunlight and heat causing the long polymer chains to break becoming shorter in length, causing the plastic to weaken.
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Plastic FundamentalsWhat Can Weaken Plastic?
Dr. Duane Priddy Sr. · July 15, 2022
The most common cause of plastic parts to weaken is exposure of the plastic to sunlight. Plastics consist of long polymer chain molecules which are entangled together, The longer the polymer chains, the stronger the plastic.
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2 min read
Plastic FundamentalsHow Does Plastic Decompose?
Dr. Duane Priddy Sr. · July 5, 2022
When the C-H bonds react with oxygen, the polymer chains break causing the plastic to degrade, weaken, and become brittle.
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1 min read
EnvironmentDoes Plastic Ever Go Away?
Dr. Duane Priddy Sr. · July 3, 2022
Generally, it takes many decades for plastics to degrade in the environment. Plastics degrade by oxidation and hydrolysis
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1 min read
Plastic FundamentalsDoes Plastic Have Fatigue?
Dr. Duane Priddy Sr. · June 24, 2022
Repeated cyclical stress events causes the crack to propagate deeper until the crack works completely through the part and it fractures.
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Plastic FundamentalsAt What Temperature Does Plastic Become Brittle?
Dr. Duane Priddy Sr. · June 24, 2022
Every plastic has a ductile to brittle transition temperature (DBTT), and it rises as parts age. Polycarbonate is tough at room temperature but shatters at -40°F.
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Plastic FundamentalsWhy Does Plastic Crack Over Time?
Dr. Duane Priddy Sr. · June 24, 2022
Plastic cracks for two reasons: natural aging over its service life, and chemical exposure that softens it and causes environmental stress cracking (ESC).
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Plastic FundamentalsHow Does Polycarbonate Fail?
Dr. Duane Priddy Sr. · June 17, 2022
PC readily absorbs many hydrocarbon chemicals causing it to become brittle and fail by a process known as Environmental Stress Cracking.
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5 min read
Pipe FailurePEX Failures Due to Manufacturing Defects
Dr. Duane Priddy Sr. · January 24, 2022
PEX will degrade by oxidation and become brittle if it is not stabilized by mixing antioxidants into the wall of the tubing.
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3 min read
Pipe FailurePEX Installation Defects
Dr. Duane Priddy Sr. · January 21, 2022
PEX failure can occur when installation rules are not followed. One installation defect is bending the pipe to make a directional change.
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3 min read
Pipe FailureCPVC Remediation From Incompatible Fire Caulk or Acoustical Caulk
Dr. Duane Priddy Sr. · February 23, 2021
Incompatible CPVC caulk can cause issues with wall penetration in sprinkler pipes, we look at the remedy when incompatible caulk is used.
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1 min read
Pipe FailureRepairing Frozen CPVC Pipes
Dr. Duane Priddy Sr. · February 22, 2021
CPVC pipe can break and cause issues that need immediate attention, this study looks at those issues and ways to fix the problem.
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3 min read
Pipe FailureWater Damage From Frozen Pipes Leads to Mold
Dr. Duane Priddy Sr. · February 21, 2021
Water damage from frozen pipes can lead to a mold-issue in homes. We look at the ways to stay educated on prevention for this issue.
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1 min read
Plastic FundamentalsWhat is Environmental Stress Cracking and How do I Stop it?
Dr. Duane Priddy Sr. · February 17, 2021
Environmental Stress Cracking can result in damaged plastics unless managed properly, so we look at ways of preventing ESC from progressing.
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1 min read
Testing & AnalysisPlastic Failure and Cleaning Products
Dr. Duane Priddy Sr. · February 14, 2021
Cleaning products commonly contain many different types of chemicals. Some of these can breakdown the structural integrity of the plastic.
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1 min read
Product DesignWater Filter Failure Causes Water Damage
Dr. Duane Priddy Sr. · December 17, 2020
Plastic water filter housings are pressurized. Pressure surges can crack a housing that was not properly designed, causing costly water damage.
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Pipe FailureCPVC Plastic Pipe Failure
Dr. Duane Priddy Sr. · August 6, 2020
CPVC pipe failure leads to water damage and property loss. Plastic pipe failure leads to millions of dollars of property damage every year.
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2 min read
Consumer ProductsRetail Plastic Bag Failure
Dr. Duane Priddy Sr. · August 6, 2020
Defective design or manufacturing of plastic bags can lead to bag failure, causing personal injury or property damage.
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3 min read
Plastic FundamentalsCommon Causes of Plastic Failure
Dr. Duane Priddy Sr. · February 20, 2019
What causes plastic parts to fail, leading to property damage or serious injury/death? Our plastic failure labs have found that plastic part failures are generally due to...
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2 min read
Testing & AnalysisThe Power of Computer Modeling in Failure Analysis of Plastic Parts
Dr. Duane Priddy Sr. · February 18, 2019
Computer modeling of the part will often reveal the defects in the part design. Our analysis allowed us to demonstrate that plastic coffee cups with flared rims are inherently defective by design.
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3 min read
Testing & AnalysisForensic Failure Analysis of Plastic Parts
Dr. Duane Priddy Sr. · February 12, 2019
To determine the root cause of plastic failure, our experts conduct thorough and comprehensive analysis testing in our state-of-the-art labs using this four-step process...
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4 min read
EnvironmentAn Expert’s Perspective on Plastic Recycling, Poverty and the Environment
Dr. Duane Priddy Sr. · February 8, 2019
The low rate of recycling of plastics is caused by human behavior. Most people are in a hurry and choose to take the path of least resistance. Since it takes extra effort and time to recycle, most people don’t.
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Testing & AnalysisPreliminary Chemical Compatibility Testing of An Experimental CPVC Fire Sprinkler System Antifreeze
Dr. Duane Priddy Sr. · January 8, 2019
Currently the only antifreeze which is approved for use in CPVC fire sprinkler piping by NFPA 13 is glycerin. However, glycerin is flammable.
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Pipe FailureSelecting the Best Remediation for Failing CPVC Piping Systems
Dr. Duane Priddy Sr. · January 8, 2019
Choosing the right remediation for a failing CPVC piping system depends on the root cause of failure and how far the contamination has spread.
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2 min read
Pipe FailureWhy Do CPVC Pipes Occasionally Fail?
Dr. Duane Priddy Sr. · January 8, 2019
A pipe or fitting may fail, it often can be linked to improper installation and occasionally to defective manufacture of pipes and fittings
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3 min read
Testing & AnalysisPredicting Service Life of Plastic Parts Using Accelerated Laboratory Tests
Dr. Duane Priddy Sr. · January 7, 2019
There is a need to develop accelerated laboratory testing methods that reliably can predict the useful life of plastic parts.
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3 min read
Testing & AnalysisWhy Do Polycarbonate Windows Sometimes Turn Yellow?
Dr. Duane Priddy Sr. · January 7, 2019
Rapid discoloration of polycarbonate (PC) is a material defect caused by incomplete end-capping of the PC polymer chains during manufacturing.
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4 min read
Pipe FailureCommon Causes of Failure of AWWA C900 PVC Pipes
Dr. Duane Priddy Sr. · January 4, 2019
PVC pipes occasionally fail due to a number of reasons including defective pipe manufacture, defective installation and defective operation...
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5 min read
Consumer ProductsHow “Burst Resistant” Exercise Balls Can Explode Causing Serious Injury
Dr. Duane Priddy Sr. · January 4, 2019
Expert witness and forensic failure analysis services of plastics including exercise ball injury caused by exercise ball failure and exercise ball...
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4 min read
Medical DeviceAre Polypropylene Mesh Implants Safe?
Dr. Duane Priddy Sr. · January 3, 2019
If the polypropylene mesh implant is very thin, has a high surface area, and is exposed to a highly oxidizing environment, the surface layer of the mesh will rapidly begin to degrade and become brittle.
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5 min read
EnvironmentThe Impact of Plastics on the Environment
Dr. Duane Priddy Sr. · January 3, 2019
The benefits that plastics bring to our lives are accompanied by concerns about the impact that waste plastics have on the environment. Are biodegradable plastics the answer?
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4 min read
Pipe FailureThe Importance of CPVC Fire Sprinkler Piping Inspection
Dr. Duane Priddy Sr. · January 3, 2019
Want to avoid CPVC fire sprinkler pipe failure? Read our guide on what causes fire sprinkler pipe fittings and material to fail and how a professional non-destructive inspection can prevent it.
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5 min read
Pipe FailureWhich Plastic Pipe is More Reliable: PEX or CPVC?
Dr. Duane Priddy Sr. · January 3, 2019
CPVC and PEX are the most common plastics used for potable water piping. These types of piping systems each have their pros and cons. Types of PEX include...
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3 min read
Pipe FailureAre Plastic Pipes Reliable?
Dr. Duane Priddy Sr. · January 3, 2019
An in-depth look at the rise and fall of polypropylene (PP) plastic piping in America. Polypropylene plastic is about 10 times more prone to oxidative degradation than PE and PEX.
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1 min read
Product DesignCause of Worm-Tracking of Chrome Plated ABS Bumpers
Dr. Duane Priddy Sr. · December 19, 2018
We analyzed a worm tracked bumper comparing areas where the chrome plating adhesion was good and where it was bad to identify the problem.
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1 min read
Testing & AnalysisFiber Optic Not Resistant to Corrosive Chemicals
Dr. Duane Priddy Sr. · December 19, 2018
The problem that required a solution was to find a way to make the fiber optic impervious to corrosive materials.
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1 min read
Product DesignImproved Fiber Optic Materials by Improving the Polymerization Process
Dr. Duane Priddy Sr. · December 19, 2018
Improving the fiber optic material through the optimization of the polymerization process through the efficiency of initiators.
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1 min read
Testing & AnalysisPrediction of Service Life for Plastic Parts
Dr. Duane Priddy Sr. · December 19, 2018
Plastic parts undergo chemical and physical aging. The manufacturer seeks to find the useful life of the part to determine its warranty.
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1 min read
Product DesignRedesign of Plastic Bottle Closure to Eliminate Failure
Dr. Duane Priddy Sr. · December 19, 2018
We evaluated the current design and performed computer modeling using finite element analysis to redesign and eliminate the failures.
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1 min read
Product DesignRedesign of Plastic Pail to Eliminate Failure
Dr. Duane Priddy Sr. · December 19, 2018
Our experts evaluated the current design and performed computer modeling to redesign and eliminate the failures.
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3 min read
Medical DeviceCBS News 60 Minutes Interviews Dr. Duane Priddy Sr. for Gynecological Polypropylene Mesh Investigation
Dr. Duane Priddy Sr. · May 17, 2018
I can’t...imagine anybody that’s knowledgeable in the science of plastics ever deciding that it was appropriate to use polypropylene in the human body...
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1 min read
Testing & AnalysisPVC Discoloration
Dr. Duane Priddy Sr. · December 17, 2016
The amine catalyst in the polyurethane foam backing underneath the PVC was migrating into the PVC causing it to degrade and discolor.
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1 min read
Product DesignFailure of Automotive Pulley Caused by Defective Part Design
Dr. Duane Priddy Sr. · June 7, 2016
To reduce automobile weight and increase fuel economy, automobile manufacturers are replacing metal parts with lighter-weight materials.
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Consumer ProductsBlow Molded PVC Bottle Failure
Dr. Duane Priddy Sr. · May 17, 2016
Before using a bottle to contain a chemical solution, chemical compatibility testing should be performed to ensure the chemicals are compatible.
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