This document provides an overview of the uses of superabsorbent polymers (SAPs) beyond absorbent hygiene products (AHPs), which are referred to as "technical SAPs". It discusses their use in agriculture to improve soil properties and reduce water usage; in cable wrapping to prevent water penetration; in food packaging to absorb liquids; and in industrial applications like concrete construction. The agriculture market is growing due to increasing global population and food demand. SAPs can increase soil water retention and availability, aeration, and plant growth while reducing irrigation needs. Research continues to develop new SAP materials and applications.

1. Superabsorbents - get technical
The intentioninmysecondarticle of three intosuperabsorbentpolymers (SAPs)istogive some
informationontheirusesinnon-AHP areaswhere theyare oftenreferredtoas“Technical SAPs”.
Agriculture
The agricultural industryisthe fastest-growingmarketsectorforSAPs.Theiruse isnow an
establishedwaterconservationtechniqueandiswidely practised indifferentpartsof the world.The
growingpopulationandincreaseddemandforfoodindevelopingnationsare the key driversforthe
demandforthe SAP marketin these agriculture applications.The importantuse areascanvery
broadlybe categorizedinto foodproduction, gardening,horticulture,forestry,alsoandtoa lesser
extentin lawns, andinrecreational areassuchas play grounds,andgolf-courses.
The original researchinitiative intosuperabsorbentpolymerscame fromthe US Departmentof
Agriculture inPeoriaIowa(USDA - ARS). Inthe early1960s, the USDA was conductingworkon
materialstoimprove waterconservationinsoils.Theydevelopedamaterial basedonthe graftingof
acrylonitrile polymerontoabackbone of starch molecules(i.e.starch-grafting). The hydrolyzed
productsof the hydrolysisof thisstarch-acrylonitrileco-polymergave waterabsorptionsgreater
than 400 timestheirweight. Also,the gelsdidnotrelease liquidwaterunlike fibrebasedabsorbent
structures. Chemically,these polymers were saponifiedstarch-graftpolyacrylonitrilecopolymers
and unlike mostnewSAPs beingmarketed hadsome degreeof environmental responsibility! This
polymertype quicklybecameknown as“SuperSlurper",aname whichwascoinedbyDean
Mayberryof ARS' InformationOffice.This“name”coupledwithrelevantpublicity,stimulated
thousandsof inquiries manyfromnon-agriculture interests by“lateral thinkers”(like myself) in
connectionwithabsorbenthygieneproducts(AHPs) andfromthis,a huge multimillion-pounddollar
demandforthe polymerwasprojected. (See part1in my SAP article series). Itisworthwhilenoting
that inAHP applications,developersweresurprisedthatthe fluidinsults whichcontainapercentage

2. of sodiumionsdepressedthe absorbencyof these superabsorbentssubstantially notablyunderload
whichleadtoand still involvesmuchcareful thoughtintothe use of these materials. Furthermore,
these earlySAPswere fine powders (oralternativelyfilmsorflakes) whichleadtoprocessing
problemswithAHPproducersunusedtohandlingthese typesof material).
Of note isthat SAPsmade withoutstarchare referredtoas “syntheticcopolymers.”Basedonolefin
derivedpolyacrylate technology,almostall suchsyntheticSAPsare usedinbabydiapers,adult
diapers,catamenials,hospitalbedpads,cable coating,andthe like.Today itisestimatedthatthe
marketfor totallysyntheticcopolymerSAPs willbe worthabout$7.96 billionby2020 worldwide.(1)
The initial patents fromthis USDA work,all issuedin the 1970’s by Weaveretal (2) (3) (4) described
the formationof a class of materialsreferredtoas“superabsorbentpolymers”(SAPs).Since then,
manypatentsrelatingtothe use and formationof agricultural SAPshave issued. More recentwork
has takenplace intoimprovingthe presentationof these starchgraftSAPsfromthe formats
describedabove tofacilitatetheiractual application(5)
Overtime,many technologicallyimprovedSAPsusedinsoil amendmentsapplications have been
basedon cross-linkedacrylic-acrylamideco-polymerswithpotassiumneutralization.Thoughtoxic
intermediatesare sometimesusedinthe manufacturerof these polymers,cross-linkedSAPsused
for soil amendmentsare non-toxic,inertwithincreasedshelf lifeandlastforyearsin the ground.
Takingthese agricultural SAP applicationsinmore detail,technologically,earliereffortsusingSAPs
for soil amendments,predominantlyingreenhouse applications,provedunsuccessful due of their
lowswell andhighcostper unitwaterheld.However,furtherresearchhelped,developingSAPsthat
improvedsoil wateravailabilityandholdingcapacity, andalsoenablingthe intake of oxygenintothe
soil,whichisnecessarytosupportrootdevelopmentandgrowth. (6)
Importantly,one needstonote thatinconsideringSAPs, aerationinplantingmixesismuchmore
difficulttomanage thanmoisture,becauseif moisture deficiencyexists,frequentirrigationcanbe

3. employed.However,if anaerationdeficiencyexists,the plantmustbe removedandthe growing
environment(rootzone) modifiedwithlargerparticlestoimprove drainageandporosity.
The applicationof SAPsdirectlytosoil canresultin earlierseedgerminationand/orblooming,
decreasedirrigationrequirements,increasedpropagation,increasedcropgrowth,increasedcrop
production,anddecreasedsoil crusting.
The amount of waterretainedinthe soil isdeterminedbysoil particle size,asthe largerthe particle
size,the lessthe abilitytoattractand retainwater,andconversely,the smallerthe particle the
greaterthe abilitytoattract and retainwater.Because aerationandretainedavailable waterare
directlyassociatedtolargersoil particlesandwaterretentionand lackof aerationare directly
associatedwithsmallersoil particles, the growingmediumforplantshasperplexed growersfor
years.Usingmore stable SAPmix componentsisamajor steptowardimprovingproductionand
controllingproblemsassociatedwith traditional managementof agrowingmedia.A major
advantage of usingSAPsistheirabilitytomake use of moisture presentinsoil suchasclay,and
make it available tothe roots.SAPamendedsoilshave betternutrientrelease,highnitrification,
reducedmicrofloraand bacterial content.(6)
Hence,the overall benefitsfromSAP usage include improvedsoil drainage, also, reducedpesticide
use,improvedfertilizerusage,andreducedirrigationwateringby30% to 50% as well as reduced
labourcosts,as plantsare wateredona schedule betweenfieldcapacityandwilting. Personal
scrutinyhas shown thatover90% of moisture heldbySAPas itexpandsandcontracts isavailable to
the plant,therefore suggestingthatnoothercomponentusedingrowingmixesprovidesthismuch
retainedwatertothe plant.
The global marketfor superabsorbentsinagriculture isestimatedataround$327.4 millionby2023.
(7) It has beensuggested inpersonal communications thatthe Asia-Pacific,Middle EastandLatin

4. Americaareaswill be majorgrowth areas. AHPscontinue toremainthe largestenduserfor SAPs.
The followingchartfromGrand ViewResearch(8) andattachedcommentsare mostinformative.
U.S. superabsorbent polymersmarket revenue by application,2012-2022, (USDMillion)
“The global superabsorbentpolymersmarketwasmajorlydominatedbythe babydiapers
application.Thissegmentheldover70% of the total marketshare in2014. The huge marketshare of
the baby diaperssegmentcanbe attributedtoitsever growingdemandinthe developingnations.
However,the agricultural segmentof the superabsorbentpolymersisexpectedtowitnessthe
maximumrate of growth,at an anticipatedCAGRof 6.0%, from 2015 to 2022. Theyare utilizedin
the regionshavingwaterscarcityforretainingwater. These polymersenhance the efficiencyof
waterusage,developbetterpropertiesof soil,andincrease the cropyield,whichisexpectedtofuel
the demandinthe agricultural segmentinfuture.”(8)

5. It needstobe notedthat agricultural companiesthatmarketseed,fertilizer,herbicides,insecticides,
and otheragricultural materialshave foundlittle use forthe totallysyntheticcopolymerSAPs as
usedinAHPs in agriculture since evaluationsof these SAPsshow poorperformancebecause theyare
composedof small,fine particleshavingan80 meshsize.One inherentlimitationof fine-mesh
particlesisthattheycannot be usedintypical granule applicatorswhichrequireparticle sizesof at
least25 mesh.Further,the SAPfilmsandpowderscannotbe appliedwithgranularfertilizers,
granularpesticides,orothergranularagricultural additives. Researchisinhandto addressthisarea
of lowparticle size. (5).
To summarize:
Agricultural SAPscanchange the physical propertiesof soilsby
• Increasingtheircapacitytoholdwater
• Reducingerosionandrunoff
• Reducingfrequencyof irrigation
• Increasingthe efficiencyof the waterbeingused
• Increasingsoil permeabilityandinfiltration
• Reducingthe tendencyof the soil togetcompacted
• Helpingplantperformance
Cable Wrap
Superabsorbentpolymers(SAP) incorporatedintotapesprovide arapidperformance duringthe critical first
minute of response towater.The SAPis generally laminatedandevenlydistributedbetweenvarious
nonwovenmaterialssothatall the SAPcontributesefficientlytothe waterblockingpropertiesof the tape.
Water swellable tapesare providedin insulative,semi-conductive,laminatedandmarine versionstosuitthe

6. cable application. Several considerationshave tobe made inthe choice of suitable SAPcontainingtapes. (9)
These include:
 Provenlongtermperformance asa replacementfortraditional fillingjelliesinoptical fibre cable
 Provennonnutritive tofungal growth.
 Fast swellingspeed.
 Thermallystable gel.
 Availabilityinarange of swellingheightstomatchthe cable maker’sspecificapplication.
 Availabilityinlonglengthstooptimizethe cable makersproductionefficiency
 Availabilityof seawatergradesforsubmarine andcostal cable installations
Superabsorbentfibres are findingincreasingusesinindustrial cables,notablywaterblockingin telecom&
electrical cables.(10)
Withelectrical cables,the thermal stabilityof SAPcontainingmaterialsisof paramountimportance andhas
beenthe subjectof researchtoaddress these concerns. (11)
Food Wrap/Packaging
In packagingformeat,fishand poultrySAPsabsorbescapingliquidsandstore these foranunlimitedtime.The
foodcan thus be transportedandstoredhygienically.Itstaysfreshlongeranddoesnothave to be repacked
so often. AccordingtoNonwovensIndustryMagazine,the beginningof the use of SAPs infoodpackagingis
oftenquoted asthe year 2000, whenbothStockhausen(withpowders) andTechnical Absorbents(withfibres)
obtainedU.S.FDA approval for theirfoodgrade superabsorbents.Bothmarketsize andpotentialgrew

7. exponentiallyfromthatdate.In2001, there waslittle superabsorbentsorrelevantnonwovensusedinfood
packaging;todaymore than one millionpoundsof superabsorbentsare usedin are usedinover20,000 metric
tonsof nonwoven(mainlyairlaid) inthe USand Europe alone.NonwovensIndustry furthercommentsthat“In
2000, small,local butchersandothermeatpackagersvaluedthe versatilityof foodpadswhichcouldbe cutto
size on-site;today,large centralizedpackagingsitesandthe desire forsafer,lesshandledfoodhasledtoa
preference forsealededge,pre-sizedpads. In2000, the ease of processingsuperabsorbentfibresand
superbsorbentfibre containingfoodpadsjustifiedthe approximatelydoubleprice (oversuperabsorbent
powders) commandedbythese products;today,withmeatpricesunderpressure,feedpricesexplodingand
acrylicacid availability possiblytobe constrained,the future of superabsorbentfibresinfoodpackagingis
clouded.”(12)
Heavy Industrial Applications
SAPsare usedinseveral typesof industrial applicationsforabsorbingaqueoussolutions.Inthese industrial
settingsthe SAPsare usedina varietyof applicationsfromsolidifyingwaterinthe drillingandminingindustry
to the constructionindustryincludingoil fracking.The polymerscanbe usedinany applicationwhere aqueous
solidificationandspill managementisof concern. (13)
Relatingtoconcrete technologythisreportisof interestasSAPsmightbe beneficialasan internal curing
agentin high-strengthconcrete.Toquote “SuperAbsorbentPolymers(SAP) are anew componentforthe
productionof buildingmaterials.Theyhave aconsiderable potential withregardtoapplicationin
construction. (14)
The state-of-the-artreportof the RILEMTC 'Internal Curingof Concrete'gave anaccount of the positive
effectsof the use of SAPin High-StrengthConcrete(HSC) asanefficientinternal curingagent.Throughthe use
of SAP,self-dessicationandcorrespondinglyautogenousshrinkage of HSCcouldbe reducedorevenavoided,

8. by providinginternal waterreservoirs.Because of theirveryhighwaterabsorptioncapacity,the polymers
have a theoreticallyhighereffectivenessthanothermaterials(e.g.lightweightaggregates).The workof TCICC
triggeredandintensifiedthe researchonSAP.A numberof researchersinvestigatedthe effectsof addingSAP
to concrete on itsrheological behaviourandshrinkage aswell asonthe strengthdevelopment.The findingsof
these investigationsare partlycontroversial, whichcanto some extentbe ascribedtothe sensitivityof the
resultsonthe type of SAP,the amountof additional mix waterandothervariationsinthe examinedconcrete
compositions.SAPparticlesare knowntosignificantlyexpandasaresultof their waterabsorption.This
influencesthe workabilityof the freshconcrete.The creationof biggerporesonone handandthe continuing
hydrationof cementdue toadditional watersupplyonthe otherhand,are expectedtoinfluencethe overall
mechanical behaviourof concrete anditsdurability.A careful laboratoryanalysisof these phenomenashould
be performed,beforerecommendingSAP-basedindustrial applicationsonalarge scale.
Besidesthe utilizationasaninternal curingagent,some otherprospective applicationsof SAPinconcrete
appearpromising(e.g.regulatingthe viscosityof the mixtureduringsprayingprocess,increasingof frost
resistance etc.).Furthermore,thereare researchactivitiesonthe use of SAPas waterregulatingagentinother
buildingmaterialswithinorganichydraulicandnon-hydraulicbinders.However,verylittle isknownonthe
resultsof thiswork.”
I will conclude thisarticle byareference tothe future.Superbsorbenthydrogelsare underactive researchbya
spin-off companyof Tu-Delftinthe Netherlandsusingnatural biopolymersderivedfromarange of renewable
resourcesincludingsewage sludge fromthe DutchNEREDA process.(15) (16) “Waste to SAP”is potentially
completelyfeasibleandmanylowpricednew SAPswill be attainable, several applicabletothe areasdescribed
inthisarticle.Watch thisspace!
The third article in thisSAPserieswill addressthe use of SAPrelatedtechnologiesinthe medicaldevicesarea
– a large topicmeritingafull article initsown right!
Dr. Edmund H Carus (August 1st, 2016)

9. Bibliography
1. Markets andMarkets at http://www.marketsandmarkets.com/PressReleases/super-absorbent.asp
2. Weaveretal “Highly absorbentstarchcontainingpolymericcompositions”USP3,981,900
3. Weaveretal “Highlyabsorbentstarchcontainingpolymericcompositions”USP3,997,484
4. Weaveretal “Highlyabsorbentgraftcopolymersof polyhydroxypolymers,acrylonitrileandand
acryliccomonomers”USP4,124,863
5. Doane “Methodsof formingsuperabsorbentpolymerproductsforuse inagriculture”USP7,009,020
6. Nnadi FN (2012) SuperAbsorbentPolymer(SAP) andIrrigationWaterConservation.IrrigatDrainage
SysEng 1:e102. doi:10.4172/2168-9768.1000e102
7. PrashantKolekarat https://www.linkedin.com/pulse/superabsorbent-polymer-sap-market-
agriculture-reach-us3274-kolekar
8. “SuperAbsorbentPolymersMarketAnalysisByApplication(Agriculture,BabyDiapers,Adult
Incontinence Products,FemaleHygiene Products,Others) AndSegmentForecastsTo2022” Grand
ViewResearch July2016 ISBN Code:978-1-68038-617-2 at
http://www.grandviewresearch.com/industry-analysis/super-absorbent-polymers-market
9. “Water Swellable Tape”Scapaat http://www.scapa.com/en/WaterSwellableTape
10. “IMPROVEMENTS IN SUPERABSORBENT WATER BLOCKINGMATERIALS FOR NEW POWER CABLE
APPLICATIONS”Czuprynaetal,Jicable 07at
http://www.jicable.org/2007/Actes/Session_B9/JIC07_B93.pdf
11. Benjaminetal “WovenFiberglasscable wrap”USP6,003,565
12. “The Future of SuperabsorbentsinFoodPackaging:NonwovensPowdersorFibers?”PhilMango
NonwovensIndustry2011 - http://www.nonwovens-industry.com/issues/2011-10/view_features/the-
future-of-superabsorbents-in-food-packagi#sthash.FJuiyriA.dpuf
13. “Waste Lock® Oil Absorbents - TOTALSORB™ Plus”athttp://www.m2polymer.com/html/oil-

10. absorbents-total-sorb-plus.html
14. “Applicationof superabsorbentpolymersinconcrete construction”Dr.-Ing.ViktorMECHTCHERINE,
RILEM TC 225-SAP 2014 at http://www.rilem.org/gene/main.php?base=8750&gp_id=241
15. The NEREDA Processat https://www.royalhaskoningdhv.com/en-gb/innovation/world-water-
day/nereda-the-essence-of-innovation
16. SlimyGreenStuff BV at http://slimygreenstuff.com/who-are-we/