Forensic Polymer Engineering. Why Polymer Products Fail in Service

414 Pages·2016·228.02 MB·English

by  Peter Rhys Lewis

FORENSIC
POLYMER
ENGINEERING
WHY POLYMER PRODUCTS
FAIL IN SERVICE
SECOND EDITION
P R L
ETER HYS EWIS
AMSTERDAM(cid:129)BOSTON(cid:129)CAMBRIDGE(cid:129)HEIDELBERG
LONDON(cid:129)NEWYORK(cid:129)OXFORD(cid:129)PARIS(cid:129)SANDIEGO
SANFRANCISCO(cid:129)SINGAPORE(cid:129)SYDNEY(cid:129)TOKYO
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Dedication
This book is dedicated to the students of Forensic Engineering everywhere.
Preface to the Second Edition
FollowingonfromthesuccessofthefirsteditionofthisbookpublishedbyWoodheadin2010,andnowbyElsevier,
itispleasingtoreportthatthesecondeditionpresentscolourfiguresforthefirsttimeandanexpandedlistofnewcase
studies.Whileblack-and-whiteimagesareinevitableforsomemicroscopicmethodssuchasscanningmicroscopyor
SEM,colourimagesarethenormwhenpublishingontheWorldWideWeb, or when submittingan expert report to
clients, or in Wikipedia articles forexample. Colour is often vital for photography of polymerproducts,where UV
degradation, for example, leads to fading of primary colours, and the change in colour is an important part of
diagnosisofthebasicproblem.SeveralsuchcasesarediscussedinChapters1and2andelsewhere.Othertypesof
degradation(especiallythermalattack)canleadtosimilarcolourchanges.
Althoughitisonly6yearssincethepublicationofthefirstedition,productfailureshavecontinuedapace,partly
duetotheongoingmarchofglobalizationwithmanynewmanufacturersofexistingandnewproductsenteringthe
market. Not all of the problems of quality assurance and product testing may have been appreciated by those
manufacturers,andconsumersoruserssuffertheconsequences.Oneproductareaismuchmoreactivethanothers,
medicaldevices,implantsandprostheses,wherepolymerproductsusuallypredominateowingtothesimilarityof
their physical properties with those of skin, bone, muscle and tendon (Chapter 3). Medical devices are sold at a
premium over other products owing to the need to meet stricter regulations and standards, with extra control of
polymer input (including additives) and testing under realistic conditions which mimic those the implant will
experiencewhenimplantedinthebody,andoverextendedperiodsoftime.TherecentscandalofthefailureofPIP
breast implants highlights the problem of good design and materials not just for use in the body but also for
manufacture and use of medical grade polymers free from additives and contaminants. But it also casts a shadow
overtheuseofsiliconepolymerforstressedimplants,andtheneedfordesignerstothinkcarefullyabouttheloads
suchimplantsmustwithstandtosurvive[1].Suchproductsmustalsobewellmade,apointshownbythefailureof
several Foley catheters, another silicone product, and discussed further in Chapter 3. Some of the cases were pub-
lishedseparatelyin2012inabookdevotedtomedicalpolymers[2].
Anothertopicwhichraisedconcernsacrosstheglobeoccurredwhenlaptopssuddenlyburstintoflames,orworse,
exploded.Itwaseventuallytracedtofaultylithiumbatterieswhichpoweredthedevices,andChapter5includesa
newcasestudyoftheaccidentcausedbyasmalllithiumbatteryinagunsight.Suchbatterieshaveaveryhighenergy
density,andtheelectrolyteisorganicsoshort-circuitscanigniteitifasparkjumpsanygapsininsulation,forexample.
Polymersealsalsohaveacriticalroletoplayinpreventinglossoffluidsfrompipes.Pneumaticsystemswidelyusedto
controlthedoorsofcommutertrains,forexample,dependonsmallpolyethyleneseals,andiffaulty,canpreventdoors
opening(andhaveevenbeenknowntostoptrainssincetrainsafetyiscompromised).Onesuchstudyshowedthat
sealsfailedtooearlyinfatiguetestsowingtoaminuteweldlineformedatoneedge.Butitwasonlyfoundusinghigh-
power microscopy (Chapter 7).Composite materials are slowly penetrating workplace products,suchas tools and
ladders.Onesuchexampleistheuseoffibre-reinforcedplasticinscaffoldingsystems,whichoffernon-conducting
andlightmaterialsforuseinaccessinghighplaces.Butonesuchproductfailedcatastrophicallywhenahorizontal
bargavewayundertheuser,andheplummetedtothegroundbeneathandwasinjured.Thejointsholdingthebarhad
cracked, and the problem was traced to faulty moulding (Chapter 8). Plastic chairs continue to present problems,
especiallyuseofrecycledpolymersintonew,apracticewhichpresentsdangersofabuild-upoflevelsofdegraded
polymer(Chapter8).Problemswithozonecrackinghaverecurredinautomotiveproducts,asdiscussedforaircraft
tractorsinChapter9.
The use of lightweight polymer materials continues in a very wide range of consumer products, such as steam
cleaners,hotwaterbottlesandheatpads,newcasesreportedinChapter10.Itisworthemphasizingthatmostofthe
cases reported in this book were produced as a result of requests from solicitors for assistance in cases involving
personalinjury,lossofpropertyordamageorinfringementofpatentordesigns.Theproductionofsuchexpertreports
hastomeetmanydemandingcriteria,mostofwhichwillbefamiliartothosewhopublishinthephysicalsciences,
suchaspreservinguniqueevidencesothatotherscanstudythesameevidence,andtakinganunbiasedviewwhen
interpretingthatevidence.Somebiasmaybeinevitable,butcanbeamelioratedbyblindtests,forexample,andby
rigoroususeofindependentmethodsofanalysis.Italsohelpstohaveseveraldifferentkindsofanalysistoexaminea
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PREFACETOTHESECONDEDITION
problem,soforexample,severalindependentmicroscopicmethodsareoftenusedtoexamineonefracturesurface.
Thisandotherexamplesarediscussedinthecasestudiesexaminedinthisbook,especiallywherelitigationproceeded
evensometimestoatrialoftheactionincourt.Expertevidenceofthekinddiscussedinthisbookreliesonnotjustthe
integrityoftheinvestigator,butalsomanywaysinwhichtheevidencecanbecheckedindependentlytoimproveits
quality[3].
PeterR.Lewis
[email protected]
References
[1] W.Peters,H.Brandon,K.L.Jerina,C.Wolf,V.L.Young(Eds.),BiomaterialsinPlasticSurgery:BreastImplants,WoodheadPublishing,2012.
[2] M.Jenkins,A.Stamboulis(Eds.),DurabilityandReliabilityofMedicalPolymers,WoodheadPublishing,2012.
[3] P.R.Lewis,K.Renolds,C.Gagg,ForensicMaterialsEngineering:Casestudies,CRCPress,2004.
Preface to the First Edition
Forensic methods have improved dramatically in recent times, increasing the chances of catching criminals,
resolvingdisputesandenhancingproductquality.Itiscommonknowledgethatforensicsciencehasenabledmany
old,coldcasestobesolved,especiallyunsolvedmurderscommittedyearsago,providedtheevidencewaspreserved
atthetimeformodernanalysis.Buttherehasbeensimilar,althoughlesswellknown,progressinforensicengineering,
the subject that deals with accidents, disasters and product failure of all kinds. Modern techniques have shed
much light on the Tay and Dee bridge disasters, for example; disasters from a different era of technology [1, 2].
Re-examination of theremaining evidencefrom oldrailwayaccidents suchasthat at Shipton-on-Cherwellin1874,
haverevealedthenatureofthefracturewhichderailedanentiretrain,causing34deathsamongthepassengers[3].
MetalfatiguewasanimportantfailuremodeintheseVictoriandisasters,butwasforlongunrecognizedandfailures
continuedwithoutrespite.Despitetheadvanceinunderstandinginthe20thcentury,theproblemcontinuesdownto
thepresentinallengineeringfields.
Whilecasestudiesofmetalproductfailure arewellpublished today, thoseof othermaterialsremain neglected,
especiallyofnon-metalssuchasglass,ceramicsandpolymers.Failuresofplasticandelastomericproductsarepoorly
published,perhapsanotunexpectedproblemgiventhereluctancebycompaniestoadvertisetheirfailures,academic
disdainofpracticalsubjects,andtheirrelativelyrecentintroductionasengineeringmaterials.However,somerecent
compilations have added much new and useful information of direct use to product designers. They include the
pioneeringbooksbyMeyerEzrin[4],DavidWright[5]andJohnScheirs[6]aswellasourownpreviousworkwhich
presented a wider view of both metal and polymer product failures [7]. In that book, we presented our cases as a
narrativefromfailuretocauseoftheproblem,withdetailsthatareoftenignored,suchas:
(cid:129) the parallelsbetween failuresin different materials
(cid:129) previous examplesof similar failures
(cid:129) alternativeinterpretations by other investigators.
Manyfailuremodes,forexample,arecommontomanydifferenttypesofmaterial,especiallyfatiguefromrepeated
loading below the nominal failure loads, corrosion or changes in a material as a result of interaction with its envi-
ronment, creep rupture, wear and other mechanisms. So knowledge in one discipline can provide clues as to how
failure occurred in other areas. Knowledge of several subjects is, indeed, often essential when products made of
severaldifferentmaterialsfail,suchasthebridgebearingdiscussedinChapter2.Thetrackrecordofparallelproduct
failuresisanothertopicofoftenvitalinterestbecausemuchwillalreadyhavebeendeterminedandcausesestablished,
providing a context for a current investigation. Thus the information from the USA about an ongoing court case
involvingthermoplasticpipeswascrucialinresolvingacaseinvolvingapipejunctionfailureintheUK(Chapter6).
Whilesuchinformationwasfrequentlyobscureinthepast,theworldwidewebisexposingmanysuchcasestopublic
viewandeasyaccess.Itcannotonlyhelpresolvedisputes,butalsoaiddesignersinselectingmaterialsknowingthe
environmentinwhichproductshavetoperformreliably.
A third area we have emphasised both here and in our previous book is the role of alternative failure expla-
nations.Moreoftenthannot,completeinformationisrarelyavailabletotheinvestigator,soassumptionsaboutthe
loads and environments must be made in order to pursue the failure causes. Litigation cases frequently restrict
importantinformationfromonesideoranother,atleastuntilthedisclosurephase,requiringtheinvestigatortokeep
anopenmindaboutthefailureorfailures.Butsomeinvestigatorsjumptoconclusionswhichareoftennotjustified
bytheevidence,andthatopinionoftencoincideswiththeviewsoftheclientwhoisfundingtheaction.Clientbiasis
in fact very common, but must be resisted when performing an investigation. It is in that client’s own long-term
intereststoknowjusthowaproductfailed,whichisthefunctionofanindependentinvestigation.Ifbiascreepsinto
a report, then costs mount as litigation proceeds to an inevitable and unfavourable conclusion. It is far better to
know the bad news early rather than later, a seemingly obvious comment, but one frequently missed during
litigation.
Sowehaveincludedclearevidenceofmisleadingormistakenreportsfromotherinvestigators,suchasthatfroma
studyofradiatorwashercracking(Chapter7),whereareportmadeincorrectdeductionsfromthefailedwashers,and
xiii
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PREFACETOTHEFIRSTEDITION
reached thewrong conclusions. Much extra work wasthen needed to fi nd therealcause of the problem. Another
exampleisgiveninChapter10.Itinvolvedcrackedtransformerplugswhichcouldelectrocutetheuser,aproblemthat
wasraisedbythesupplierintheUK.TheyimportedtheplugsfromJapan,andthecaseswereinturnmadeinChina.A
Japanesegroupsuggestedacausewhichwecouldnotconfirm,andtheyusedasinglemethodratherthanrelyingon
severalindependentmethods.Wesuggestedaquitedifferentsourceoftheproblem,faultymouldinginChina.The
Chinese produced moulding records which confirmed our diagnosis, and the problem was solved for the affected
batchofplugs.
Missing evidence is another problem often faced by the investigator. It is prevalent of course in fi res, the key
initiation point frequently destroyed by the fi re itself. However, traces which do survive can hold the key to the
solution of the problem, as discussed in more detail in Chapter 9 dealing with vehicle accidents. The material
evidenceinmedicalfailuresisalsosometimeslost,especiallyiftheproductisdisposable,suchaswithsuturesused
to stitch wounds (Chapter 3). Other agencies may lose samples, and failed samples may be discarded after in-
spection by the manufacturer, as in other cases discussed in Chapter 3. The extra uncertainties introduced make
investigation yet more difficult, and explains why many legal cases take so long to resolve. Poor reporting on
failures is not endemic to litigation but extends into the domain of the designer and manufacturer, where failed
products should be studied in depth so as to prevent future failures. It is one hope that this and other failure
compilations will help reverse that problem, by making failure case studies much more widely available to the
specialist engineer. One way it can be achieved is by publication in learned and technical journals, and one such
journalthathasestablishedafirmfoundationisEngineeringFailureAnalysiseditedbyDrDRHJones.Anincreasing
numberofspecialist papersdealingwithnon-metalsaretobefound there,helpingtowidenaccesstothestudy of
productfailureandwaystocircumventthemanyproblemsthatensue.Someofthecasespublishedinthisbookare
alsopublishedinthatjournal.
The theoretical basis for the study of polymeric product failures is established and laid down in Chapter 1,
along withthe specialterminologyneededwithlongchain materials.Polymerscienceisarelativelynewsubject,
dating back to the 1920s, although materials like gutta-percha(insulationinelectricalandcommunicationcables),
natural rubber, celluloid and Bakelite were well exploited in the Victorian period. New polymers are still being
synthesized,andanunderstandingofthebasicsisnormallyneeded,evenwhenexaminingwell-knownpolymers
such as polyethylene, which displaced gutta-percha for cable insulation in the 1930s. The analytical tools used for
examining failed products are discussed in Chapter 2 with some background to their utility, publication and
limitations. A compilation of both common and specialist terms of use throughout this book is also available
elsewhere[8].
The case studies proper begin at Chapter 3 with an examination of failed medical products, both transitory
andpermanentimplantswithalargepolymercomponent.Itisoneofthemostactiveareasofinterest,andunlike
many other areas, reasonably well published in the specialist medical literature. Chapters 4 and 5 encompass
largeandsmallcontainers,wherepolymersarewellestablishedasmaterialsofconstruction.Bothsmallandmuch
larger failures can lead to extensive collateral damage when the fluid contents are released by cracking of the
container walls. Pipes are discussed in Chapter 6, where polymers have revolutionized practice, especially for
utilitytransportation.Butmistakesinusingpolymershaveoccurred,andonesuchproblemwassowidespreadin
NorthAmericathatitresultedinoneofthelargest,mostexpensiveandlongrunningclassactionsever.Polymers
have long been used for sealing pipe systems, and they are the subject of case studies in Chapter 7, including an
example of a very expensive problem in a pneumatic system controlling a semi-conductor fabrication factory in
Japan. Rubber seals failed and shut down several machines, not just once but several times, leading to loss of
production.
Tools and related products follow in Chapter 8, and include products such as knife handles, power tools and
laddersaswellasall-plasticfurniture.Whensuchproductssuddenlyfail,thesafetyoftheuserisimmediatelyatrisk.
Moderncars containmanyhiddensafety-criticalcomponents suchasfuellines,aswellasvisibleproductssuchas
tyres. Failure can have devastating consequences in driven vehicles, including both motorbikes and trucks.
Road traffic accidents are the subject of Chapter 9, which on investigation proved to be traceable to the failure of
polymercomponents.Polymersareubiquitousinconsumerproductssuchaselectricalinsulationinplugsandother
electricalequipment,wherefailurecanresultinelectrocution,sogreatcareisneededtopreventfailure.Theyarealso
used for key anchors in luggage and baby cots, for example, where failure can result in serious personal injury
(Chapter10).
Webelievethatitisonlybypublicizingcasestudiesofproductfailurethatdesignersandproducerswillchange
theirpracticesandprocedurestoeliminateriskstousers,improvingnotjustproductsafetybutalsotheirownrep-
utationsasmanufacturers.Anditisnotasifmanyofthedesignchangesneededarecostlyordifficulttomake.Asingle
xv
PREFACETOTHEFIRSTEDITION
examplewillsufficeamongthemanydiscussedinthemaintext.Thestrengthofmanyproductscouldbeincreased
easily by ameliorating stress concentrations, especially sharp corners on the inner sides of enclosures. It can be
achievedbyroundingoutsharpcornersontooledgesandcorners,anoperationtakingonlyafewminutesdepending
ontoolcomplexity.Manyotherexamplesaredescribedinthetext.
References
[1] PeterR.Lewis,BeautifulRailwayBridgeoftheSilveryTay:ReinvestigatingtheTayBridgeDisasterof1879,Tempus,2004.
[2] PeterR.Lewis,DisasterontheDee:RobertStephenson’sNemesisof1847,TempusPublishing,2007.
[3] PeterR.Lewis,AlistairNisbet,‘WheelstoDisaster!:TheOxfordtrainwreckofChristmasEve,1874’,Tempus,2008.
[4] M.Ezrin,PlasticsFailureGuide:CauseandPrevention,Hanser,1996.
[5] D.Wright,FailureofPlasticsandRubberproducts:Causes,EffectsandCaseStudiesinvolvingDegradation,RAPRA,2001.
[6] J.Scheirs,CompositionalandFailureAnalysisofPolymers:APracticalApproach,Wiley,2000.
[7] Lewis,PeterRhys,KenReynolds,ColinGagg,ForensicMaterialsEngineering:CaseStudies,CRCPress,2003.
[8] P.W. Walker, Peter R. Lewis, N. Braithwaite, K. Reynolds, G. Weidmann (Eds.), Chambers Materials Science and Technology Dictionary,
Chambers,1993.
DrPeterRhysLewis
[email protected]
ColinGagg
[email protected]
Acknowledgements
First and foremost, we would like to thank the numerous insurance companies, loss adjusters, manufacturers,
otherexpertsandlawyersforprovidingallofthecasesinthisbook.OldhamBatteriesLtddeservesspecialmention
for their support of our work, including Dr Richard Acton, Technical Director at the time, and Bob Booth of the
Technical Department. We would also like to extend our appreciation to all those fellow experts with whom we
have collaborated and who have proved open to argument and discussion.
PRL would like to acknowledge work done by former research students, especially Drs Geoff Attenborough,
Dave Anderton, Phil Hargreaves, Paul Hawkins, Kamal Weeraperuma and Bob Ward, and the support of Sir
Geoffrey Allen FRS in encouraging research with industry. The Consumer Research Labs and World Bank helped
support the work on PVC pipes. We also thank EPSRC for supporting our post-graduate course in Forensic Engi-
neering(T839)whichaimstoprovidestudentswithabasicfoundationinthesubject.TheearliercourseDesignand
ManufacturewithPolymers(T838)receivedsimilarsupport,bothbeingrunincollaborationwiththePolymerSchool
atLondonMetropolitanUniversityaspartofanintegratedgraduatedevelopmentschemeorIGDS.Studentsonthe
courses have participated actively in day schools, showing great enthusiasm for the subject. Our colleagues at
London Met helped produce T838, including, Drs John Brydson, Mike O’Brien, Bob Dyson and Mark Alger. Pro-
fessor Rod A Smith, FRAEng, Dr Colin Goodchild, Professor Roy Crawford FRAEng and Dr DRH Jones gave
encouragement to the project. The Royal Academy of Engineering and the Open University supported numerous
visits byPRL totheUnitedStatestoreadpapers attheFAPSIGgroupoftheSocietyofPlasticEngineersbasedon
casestudiesofpolymerfailure.HethanksDrsMeyerEzrinandDonaldDuvall,andProfessorsJanSpoormakerand
AlexChudnovskyfortheirinterestinhiswork.ThanksalsogotoRebeccaDolbey,andDrsDavidWrightandRoger
BrownofRAPRATechnologyLtdforinteractivediscussions.PRLwouldalsoliketothankstaffattheShrivenham
campus of Cranfield University during his tenure on the Forensic Engineering and Science Masters course, espe-
cially Drs Mike Edwards,John Bellerby, Donald Peachand David Lane.
Muchofthedetailedresearchdiscussedwouldnothavebeenpossiblewithoutthehelpofourmanycolleagues,
especially Drs Rod Barrett, G Weidmann, Sarah Hainsworth (Leicester University) and Jim Moffatt with technical
assistancefromGordonImlach(FTIR,DSC,SEM),StanHiller(opticalmicroscopy),RichardBlack(microscopy)and
Naomi Williams (SEM), Charles Snelling and Peter Ledgard (machining), Richard Hearne and Ian Norman (lab
superintendent). We have had stimulating discussions of the subject with Nancy Ashburn, Salih Gungor, Martin
Rist Professors Jeff Johnson, Lyndon Edwards and Mike Fitzpatrick.
We would both like to thank our families for their support, especially Sue Gagg for proofreading and David
Lewis for providing information on current coal mine practice. Dr Patrick Lewis has helped in several literature
searches involving medical device failures, and Fiona Lewis in providing administrative support.
In the preparation of the second edition, I would like to thank Dr Colin Gagg for helpful discussions. Gordon
Imlachassistedinthescanningmicroscopy(SEM)andchemicalanalysisofpolymercomponents,especiallyinfra-
red spectroscopy. Stan Hiller helped in the optical microscopy. I would also like to thank the Open University for
providing office facilities in my current appointment as Honorary Research Fellow in Forensic Engineering.
xvii
C H A P T E R
1
Introduction
1.1 Product failure their own experience. There is no better way of illus-
trating the basic principles of polymer technology than
It comes as no surprise that products have a limited
by way of a detailed case study. It focuses attention on
life in service. But what many might find surprising is
a specific aspect of the polymer structure, or the way it
the very great range of possible causes of failure, from
has been made, or the design of the product which has
a large and now very diverse range of materials. The
failed.
failure modes of most metals are well established, sim-
Sobywayofpreludetothecasestudiesdescribedin
ply because most have been used in service for many
this book, it is essential to provide the technical back-
years. They have been well studied both in the labora-
drop to the diversity of polymers used in products
tory and in practical applications, so there is a volumi-
today. They provide properties unavailable in metals,
nous literature on the way they fracture, or fail in
such as transparency, low weight, high strength and
otherways.Thatofcoursedoesnotstopfurtherfailures,
insulation. Low weight is at a premium for transport
butitdoesmakefailuresfromknowncauseslesslikely.
of goods and people, and one area where polymers
Engineersanddesignershavealargepropertydatabase
haveexpandedinuse.Thatsuccessformsthebackdrop
available to them to check whether or not a particular
to this book. After all, to understand the way materials
metaloralloyisfittobeusedunderaspecifiedsetofcir-
succeedhelpstounderstandwhytheyfail.Thestarting
cumstances.Suchisnotthecasewithmostnon-metallic
pointistherangeofnon-metalsavailableinthenatural
materials,especiallythosethathavebeendiscoveredor
spectrum of elements. General definitions of terms
invented within the recent past, especially polymers.
and some explanatory text are provided in two dictio-
Their failure mechanisms are the subject of this book,
naries [1,2].
but the usual academic approach of separating the
failure mechanism from the product which fails has
not been taken, but rather discuss each incident as a 1.2 Non-metallic elements
case study inits ownright.
Case studies are important for several reasons. First, The breadth of materials is not only very wide, but
product failures must be discussed in context, when also growing at an unprecedented rate today. To the
the cause or causes of failure can be related to the way existing fixed number of naturally occurring metals
inwhichtheproducthasbeenused(orabused).Second, (about 72 of the 92 elements) have been added many
iffurtherfailuresofaparticulartypearetobeprevented different alloys and compositions for particular kinds
infuture,thenthecausesmustbeidentifiedsoastotake ofproperties.Themuchsmallernumberofnon-metallic
remedial measures. It necessarily implies that all the elements (about 20) exerts an influence way beyond
product features which are relevant to its failure have their number, which is actually only about 14, when
to be examined for establishing the causal chain of the relatively unreactive noble gases are excluded.
eventsleadingtoitsfinaldemise.Thefirststepinestab- That select group of elements includes most important
lishing the causal chain is simply to provide a chronol- of all, the elements carbon (C), silicon (Si), oxygen (O),
ogy of events, so that each step is isolated and hydrogen (H), chlorine (Cl), fluorine (F), nitrogen (N),
sequenced. Only then can the causes be tackled, using sulphur (S) and phosphorus (P). They are abundant in
appropriateanalyticaltools.Thedetailsofeachincident the Earth’s crust and are all reactive both with one
have to be described so that the critical facts can be anotherand with the metalsto form compounds.
sorted from the mass of irrelevant detail. This enables Those compounds include polymers, ceramics and
a fuller picture of the accident to be achieved, and it is glasses, all of which provide useful solid materials.
also much more interesting to the reader if he or she But in order to understand their physical and chemical
wishes to draw parallels with related incidents within properties, a brief discussion of the way they are held
ForensicPolymerEngineering Copyright©2016ElsevierLtd.Allrightsreserved.
1
http://dx.doi.org/10.1016/B978-0-08-101055-6.00001-X