Our site uses cookies necessary for its proper functioning. To improve your experience, other cookies may be used: you can choose to disable them. This can be changed at any time via the Cookies link at the bottom of the page.


Effect of beta-nucleation on aging and crack growth resistance of polypropylene exposed to chlorinated water

 

Papers

Plastic Pipes Conference Association # 2018 Las-Vegas

Joerg Fischer, Paul J. Freudenthaler, Patrick R. Bradler, Reinhold W. Lang, Susan C. Mantell

This research addresses the effect of nucleation on the global aging behavior and the fatigue crack growth (FCG) resistance of commercial alpha- and beta-nucleated polypropylene random copolymer pipe grades (PP-R) when exposed to chlorinated water (5 mg/l free chlorine) at an elevated temperature of 60°C. Comparing the two PP-R grades, for the alpha-nucleated PP-R a significantly higher embrittlement due to exposure to hot chlorinated water was obtained in tensile tests with micro-sized specimens. In the FCG experiments with cracked round bar specimens, the beta-nucleated PP-R also outperforms the alpha-nucleated type in non-chlorinated water. Experiments with PP-beta in chlorinated water revealed a significantly reduced FCG resistance, most likely caused by enhanced local crack tip aging.

In many world regions, water is polluted with bacteria, viruses and parasites, and disinfection of contaminated water is required as a prevention of waterborne diseases. Chlorine is the most widely utilized and the most affordable water disinfectant, as it is easy to use and highly efficient against different kinds of waterborne pathogens. In this context, it is well known that polyolefins in general exhibit a significant degree of aging when exposed to water disinfectants. However, for the case of polypropylene (PP), little information is available on how the aging behavior and crack growth resistance in chlorinated water environments is affected by the material morphology. Hence, the aging behavior and crack growth resistance of two commercial PP random copolymer pipe grades was systematically investigated. One of the PP grades was of a conventional alpha-nucleated type (PP-alpha), whereas the other was specifically beta-nucleated (PPbeta). Material exposure and testing was performed at an elevated temperature of 60°C, and under environmental conditions of non-chlorinated and chlorinated water, the latter containing 5 mg/l chlorine. In addition to global aging and fatigue crack growth (FCG) experiments, tensile tests and DSC experiments were conducted. While for the microsized specimens of PP-alpha the exposure to chlorinated water at 60°C resulted in significant embrittlement after 1000 h, beta-nucleated PP-R exhibited a high resistance to chlorinated water exposure. In the FCG experiments, PP-beta turned out to be superior to PP-alpha under non-chlorinated water environment. Furthermore, in chlorinated water crack growth rates for PP-beta were found to be higher than in non-chlorinated water.

Related keywords : nucleation effects; aging; fatigue crack growth resistance; polypropylene pipe grades; chlorinated water.
Please note that the whole article content is available on PPCA website only :

Related papers

2021 Amsterdam : A NEW GENERATION OF HIGH PERFORMANCE BIAXIALLY ORIENTED POLYETHYLENE AND POLYPROPYLENE PRESSURE PIPES

Author(s) : A. Taraiya, P. Degenhart, M. Soliman, M. Boerakker, R. Handstanger, R. Kleppinger

Since the introduction of polyolefins for pressure pipes, continuous improvements have been made to meet ever-higher demands on their performance and to expand their application window beyond their original scope, mostly based on new resin formulations. Today, we also continue to push the limit to provide better...

2021 Amsterdam : A TRADE ASSOCIATION EXPLORED

Author(s) : Drew Mueller, Peter Dyke

HDPE Pipe holds a dominant position in several markets in North America: natural gas distribution, oil patch, mining, landfill and geothermal. So why are polyethylene’s municipal water and wastewater market shares so much lower than these other industries? How has the polyethylene industry been successful in growing...

2021 Amsterdam : AN EVIDENTIAL APPROACH TO USE OF POLYETHYLENE PIPE FOR HYDROGEN FUEL GASES

Author(s) : Derek Muckle

A technical program has been undertaken to provide evidence on the suitability of polyethylene pipe and fitting systems for the distribution of hydrogen fuel gas. The underlying principle has been to evaluate material in the form of a pipe and to consider the performance of the pipe and of the welded jointing systems...

2021 Amsterdam : APPLICATION OF PP-R COMPOSITE REINFORCED PIPES IN HOT AND COLD WATER SYSTEMS

Author(s) : Lei Wang, Guozhi Xu, Qiaoping Qiu, Weihua Lu, Yanwang Han

PP-R (random copolymerized polypropylene) has been widely used in hot and cold water systems. However, the standard PP-R pipes have the disadvantages of a large high-temperature thermal expansion coefficient, an insufficient notched impact strength, and a low temperature and pressure resistance. In this paper, a new...

2021 Amsterdam : APPLICATIONS OF HDPE PIPING TO SUPPLY WATER TO RURAL VILLAGES IN MOROCCO

Author(s) : Donald Swen, Leanne Pichay, Nicholas Vallin, Alice Wu, Jim Johnston

In the rural commune of Ait Bayoud, Morocco, two of the most remote villages in the area, Ilguiloda and Izgouaren, live with water scarcity. To meet their water needs, women and children walk several kilometers to the nearest spring each day, often multiple times a day. Consequently, children cannot attend school...

2021 Amsterdam : CHALLENGING THE 10% WALL THICKNESS RULE FOR HDPE MARINE PIPELINES

Author(s) : Ilija Radeljic, Ebbe Smith

HDPE pipe can be relatively easily scratched during the manipulation on the site, which is especially true for the marine pipelines. Installing the scratched marine pipe with the S bend method presents a risk and repair methods are usually performed. Currently, there is no standard defining the repair procedure, in...

2021 Amsterdam : CHEAPER AND BETTER NETWORKS REALISED WITH PRACTICAL DESIGN SOFTWARE

Author(s) : Andreas Moerman, Flip van der Valk, Mirjam Blokker KWR, Tjakko Haaijer, Jan Vreeburg,

Drinking water companies with ageing networks are facing vast amounts of drinking water network reconstructions during the coming decades. This development coincides with the energy transition, which puts pressure on the available space underground. These external drivers give drinking water companies an opportunity...

2021 Amsterdam : DEVELOPMENT OF A RAPID AND INNOVATIVE IN-FACTORY PROCEDURE FOR TESTING THE PERFORMANCES OF PE PIPES CONTAINING VARIOUS PROPORTIONS OF RECYCLED POLYMER MATERIAL

Author(s) : Dominique GUEUGNAUT, Pascal AUSSANT, Romuald BOUAFFRE, Myriam BECHROURI

Concerns regarding the environment and sustainable development have revived interest in the reprocessing and re-use of polymer materials from manufactured objects that have reached the end of their operating life. Within this framework, formal professional agreements have been put in place at global level under the...

2021 Amsterdam : EFFECT OF CHLORINATED WATER ON THE FATIGUE CRACK GROWTH RESISTANCE OF POLYETHYLENE COMPOUNDS WITH RECYCLATE CONTENT FOR PIPE APPLICATIONS

Author(s) : Paul J. Freudenthaler, Joerg Fischer, Mathias Eder, Reinhold W. Lang

For controlled water disinfection, typically chlorine is used and preliminary studies demonstrate its aging and crack growth acceleration effects on polyolefin pipe materials [1, 2]. Although the use of recycled plastics is not prohibited in some ISO standards for polyolefin piping systems [3–5], only small amounts...

2021 Amsterdam : EVALUATION OF MECHANICAL PROPERTIES AND LONG- TERM DURABILITY OF AGED POLYETHYLENE PIPES FOR GAS DISTRIBUTION

Author(s) : Shuhei Nishida, Shintaro Iwasaki, Hidefumi Yamanaka, Takahiro Kasatani

Polyethylene pipelines have been used for natural gas service applications for over 40 years in Japan. It is thought that they will continue to be used widely for many years. Therefore, it is important to confirm the conditions of the existing pipelines being used for the long term. In this study, polyethylene pipes...

2021 Amsterdam : EXPERIMENTAL DETERMINATION OF THE EFFECTS OF LIQUID HYDROCARBONS ON THE LONG-TERM CREEP RUPTURE PROPERTIES OF PRESSURE PIPE GRADE UNPLASTICIZED POLYAMIDE-12

Author(s) : James F. Mason, Akshay Ponda, Hermann van Laak, Buc Slay

The effects of liquid hydrocarbons on long term strength of pipe grade thermoplastic resins is an important consideration when designing pressure pipe for use in the oil and gas industry. There is an extensive body of work going back several decades descri bing these effects for pipe grade polyethylenes, and all...

2021 Amsterdam : FINDING THE RIGHT PIPE TEST FOR POLYETHYLENE WITH RAISED RESISTANCE TO SLOW CRACK GROWTH

Author(s) : Ernst van der Stok

For PE 100-RC, two tests are still under development for pipes: the point load test (PLT) and the accelerated notch pipe test (aNPT). The PLT was developed by a project group consisting of manufacturers and end users. The PLT determines the resistance to point loads as they can occur in practice. An earlier study...

2021 Amsterdam : FINITE ELEMENT METHOD (FEM) USED TO SIMULATE THE STRESS/STRAIN OF THE POINT LOAD TEST (PLT) IN A BROADER STUDY TO SUPPORT THE FUTURE ISO TEST STANDARD

Author(s) : S. Nestelberger, J. Cheng

The Point Load Test (PLT) [‎ 1, ‎ 2] was designed to simulate the SCG (slow crack growth) failure initiated by a rock pressing into the exterior wall of a polymer pipe. Today’s PE materials sustain long PLT testing times, due to its high SCG resistance design. Consequently, an accelerated “PLT+” with the support of...

2021 Amsterdam : FLOWABLE FILL FOR PLASTIC PIPE

Author(s) : Amster Howard

Flowable fill is used for many applications, but mainly for pipe trench embedment and backfill. There are three ways that using flowable fill can be kind to the environment. Because flowable fill is self-leveling and has a strength greater than the native soil, the trench cross section can be minimized. This means...

2021 Amsterdam : FROM MULTILAYER LAMINATES TO INDUSTRIAL PIPE APPLICATIONS – A GUIDELINE

Author(s) : Gerald Pinter, Johannes Wiener, Florian Arbeiter, Abhishek Tiwari, Otmar Kolednik

For pipe applications, catastrophic failure due to crack growth has to be prevented by all means. Techniques to develop new and even tougher pipe materials are explored in this contribution. The aim is to create a multi-layer architecture, that exhibits high toughness as well as damage tolerance towards sharp notches....

2021 Amsterdam : HISTORY OF HDPE USE AT THE CITY OF PALO ALTO FOR POTABLE WATER DISTRIBUTION

Author(s) : Greg Scoby, PE

This paper will detail the steps taken during adoption of HDPE for potable water systems improvements including material justification, creation of related specifications, investigation of available piping components, qualification of contractors and the construction/inspection of related systems. The City of...

2021 Amsterdam : INNOVATIVE MILLIMETER WAVE TECHNOLOGY FOR MEASURING THE PIPE WALL THICKNESS EARLY IN THE EXTRUSION PROCESS

Author(s) : Christian Schalich

Plastic pipes for infrastructure and building applications are precisely specified with regards to wall thickness and diameter. Pipe manufacturers use different measuring methods in order to ensure the required dimensional accuracy and maintain a constant high quality. This paper introduces a measuring system based on...

2021 Amsterdam : INVESTIGATING THE INFLUENCE OF CHANGES IN MOLECULAR STRUCTURE OF POLYAMIDE 12 GRADES ON THE RESISTANCE AGAINST SLOW CRACK GROWTH

Author(s) : Mario Messiha, Britta Gerets, Jan Heimink, Andreas Frank, Florian Arbeiter, Gerald Pinter

A majority of field failure of viscoelastic plastic pipes can be attributed to slow crack growth (SCG) and has become crucial in terms of characterization of newly developed materials – particularly, if they are designed for pressurized pipe applications. In this study, investigations in terms of SCG resistances...

2021 Amsterdam : LARGE DIAMETER & THICK WALL HDPE PIPES PRODUCED AND DEVELOPED IN THE MIDDLE EAST – 3 CASE STORIES

Author(s) : Eng. Grigorios Vigellis, Eng. Mohamed Hageb

Continuous development and innovation in the production of plastic pipes made by high density polyethylene (HDPE) has enabled the industry to produce much larger diameter systems than ever believed possible. The enablers for production of such large plastic pipes are three main pillars: continuous innovation...

2021 Amsterdam : LONG-TERM DURABILITY OF NEW POLYMER COMPOSITE VALVES FOR DRINKING WATER NETWORKS

Author(s) : Jennifer Ravereau, Jose Teixeira Pinto, Malena Bernabeu, Jose Alacid, Jean-Philippe Le Goff, Frederic Mohier, Benjamin Rabaud

Drinking water network fittings such as valves are made of brass materials known to be robust over long periods. Due to the gradual inflation metallic raw material costs, composite plastic valves have grown in market share. Uncertainties remain, however, on their long-term reliability. The aim of this work is to...

Members of the Association

BOREALISBOROUGEFormosa Plastics CorporationHanwha TotalEnergiesINEOS O&PIRPCKorea Petrochemical IND. Co., LTD (KPIC)LyondellBasellPetroChina Dushanzi Petrochemical CompanyPRIME POLYMERSABICSCG Chemicals & Thai PolyethyleneSinopecTASNEE
TOP