Poly(acrylamide-co-acrylate)/rice husk ash hydrogel composites

8/13/2019 Poly(acrylamide-co-acrylate)/rice husk ash hydrogel composites

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Composites: Part B 51 (2013)246–253

Contents lists available at SciVerse

ScienceDi rect

Composites:

Part B

journal h omepage: www. elsevier.com/loc ate/compositesb

Poly(acrylamide-co-acrylate)/rice hs! ash hydro"el

composites# $$# %emperatre e&&ect o' rice hs! ash

ote'tio'

ea' de *# C+'dido a, 'to'io .#B# Pereira , 'dr # aardo , "ila #P#*# icardo c,dith P## eitosa c, d7a'i C# 'i8 , ra'cisco 9## odri"es a, ,⇑

aCoorde'a;o de <=mica, >'i7ersidade stadal ?ale do cara@, 7# da >'i7ersidade,

A50, Camps da Bet+'ia, 62040-30 *oral-C, Bra8il epartame'to de <=mica, >'i7ersidade stadal de ari'", 7# Colomo, 5D0,

A020-D00 ari'"-P, Bra8ilc

epartame'to de <=mica Er"+'ica e $'or"+'ica, Camps do Pici, >'i7ersidade ederal do Cear, 60455-60 ortale8a-C, Bra8il

a r t i c l e i ' & o

rticle history:

ecei7ed 13

Ectoer 2012

ecei7ed i' re7ised

&orm 15 erary2013

ccepted 10 arch

2013

7ailale o'li'e 22arch 2013

FeyGords:

# Polymer–matriH

composites

(PCs) # *mart

materials

# %hermal a'alysis

http://dx.doi.org/10.1016/j.compositesb.2013.03.027




http://www.sciencedirect.com/science/journal/13598368





http://www.elsevier.com/locate/compositesb













a

s

t r

a

c

t

*perasore't

hydro"el composites

ased o'

poly(acrylamide-co-

acrylate) a'd rice

hs! ash (9)

Gere prepared y &ree-radical copolymeri8atio' i'

aIeos media, si'" , -methyle'eisacrylamide

(B), as crossli'!er a'd potassim persl&ate (F 2*

2E

A), as

i'itiator# %he e&&ect o& calci'atio' temperatres (400–

D00 JC) &or otai'i'" 9 Gas e7alated# %$, KL*,

*–* a'd %. Gere applied to characteri8e a series

o& hydro"els Mlled Gith 9# %he hydro"els composites

Gere &ormed Gith co'sta't amo'ts o& 9 (10 Gt#N) a'd

crossli'!i'" a"e't (0#1 mol-N) i' relatio' to the relati7e

to the total mass o& acrylamide (m) a'd potassim

acrylate (Fc) mo'omers (50–50 mol-N)# la'!

sample o& poly(acrylamide-co-acrylate) hydro"el

Githot 9 Gas sed as co'trol# sperasore't

hydro"el composite, Gith a maHimm asorptio' KeI

O

1000 "Gater

/"asore't

, Gas otai'ed Gith the 9 calci'ed at

D00 JC# $' additio', the hydro"el composite shoGed to e

se'siti7e to the p9 7ariatio' a'd to the pres- e'ce o& salts

i' the sGelli'" media# rom the reslts, it is possile to

i'&er that the poly(acrylamide-co- acrylate)/9

hydro"el composites prese'ted "ood characteristics to e

applied as soil co'ditio'er &or si'" i' a"ricltre#

2013 lse7ier Qtd# ll ri"hts reser7ed#

1#

$'trodctio'

*earchi'" &or tech'olo"ies co'sidered

ecolo"ically correct has ecome o& maor

co'cer' i' rece't years# %his 'eG

paradi"m o& eco- 'omic de7elopme't is

directed to pro7ide a' impro7eme't i'

Gel- &are o& &rther "e'eratio's,

i'corporati'" i' their co'ceptio' the

'eedi'" o& 'eG prodctio'methodolo"ies ale to redce the poll-

tio' a'd the e'7iro'me'tal impact# %he

lar"e amo'ts o& materials that prese't

loG de"radatio' rate at amie't

co'ditio's ha7e cased se7ere

e'7iro'me'tal, eco'omic, social a'd

ridical isses#

%he rice hs! ash (9) is a' a"ro-

i'dstrial reside reslti'" &rom the

thermochemical co'7ersio' o& rice hs!,

a'd as a Gaste, the maority o& 9

"e'erated is discarded, casi'" polltio'#

%he physical a'd chemical properties o&

9 are determi'ed accordi'" to the

methodolo"y applied to its prodctio'

(pyrolysis, "asiMca- tio' a'd/or

comstio', &or i'sta'ce) a'd y some

7ariales, sch as, type o& eIipme'temployed, r'i'" temperatre a'd

time# e"ardless the process o& r'i'",

the reslta't ash has silica co'-

⇑Correspo'di'" athor at:

Coorde'a;o de <=mica,

>'i7ersidade stadal ?ale do cara@,



7# da >'i7ersidade, A50, Camps da

Bet+'ia, 62040-30 *oral-C, Bra8il#

%el#/&aH: R55 A5 3611 6342#

-mail address:

almeidaSIimicaTyahoo#com#r

(#9## odri"es)#

te't aro'd 4–DN U1–3V# E' the

other ha'd, temperatre achie7ed

dri'" calci'atio' is the determi'i'"

&actor &or the appeara'ce o& silica i'

amorphos or crystalli'e states U4,5V#

*e7eral researchers ha7e tili8ed 9 to

prepare 8eolites a'd mesoporos

materials U6,V, as a' adsore't &or metal

io's sch as Cd2R, W'2R a'd i2R UA,DV, a'd

hea7y metal sch as lead a'd mercry

&rom aIeos soltio' U10V, as sstitte

&or ceme't U11V, as alter'ati7e sorce &or

acti7e silica prodctio' U12,13V, as Mllers

&or 'atral a'd sy'thetic rers U14–16V

a'd &or acrylamide–acrylate copolymer

hydro"els U1V# *ome or"a'ic matters,

sch as Co'- "o red a'd 7acm pmp

oil U1AV, palmytic acid U1DV, $'di"o

Carmi'e dye U20V, Brillia't .ree' dye U21V,

ethyle'e Ble dye U22V, ca' also e

asored y 9#

*perasore't hydro"els are i'solle

i' Gater a'd ca' asor a'd retai' lar"e

amo'ts o& aIeos Mids e7e' 'der

pressre# %here&ore, sperasore'ts

ha7e "reat ad7a'ta"es o7er traditio'alGater-asori'" materials# e to their

eHcelle't properties, sperasore't

hydro"els ha7e raised co'siderale

i'terest a'd they ha7e ee' Gidely sed

i' se7eral Melds, sch as, hy"ie'ic

prodcts, horticltre, "elactators, dr"

deli7ery systems, as Gell as Gater

loc!i'" tapes a'd coal deGateri'" U23–

2DV#

Based o' ao7e descriptio', this paper isa seco'd o& a series o& papers i' Ghich

sperasore't hydro"els composites

ased o'

135D-A36A/X - see &ro't

matter 2013 lse7ier Qtd# ll

ri"hts reser7ed#

mailto:[email protected]

mailto:[email protected]



http://dH#doi#or"/10#1016/#co

mposites#2013#03#02







d*# C+'dido et al# / Composites: Part B 51 (2013) 246–253

5

poly(acrylamide-co-acrylate) Mlled Gith

9 Gere &ormed# %he sperasore't

hydro"els composites Gere characteri8ed y

o- rier tra's&orm i'&rared spectroscopy

(%$), L-ray di&&ractio' (L), *ca''i'"

electro' microscopy copled to e'er"y

dispersi7e spectroscopy L-ray (*–*)

a'd %hermo"ra7imetry (%.)# $' this paper

the &ocs is o' the temperatre e&&ect o& 9

ote'tio' as Gell as o' the sGelli'"–dryi'"

capailities o& hydro"els#

2#

Hperime'tal

2#1#

aterials

crylamide (m), acrylic acid (c),

3, 3, 30 , 30 -tetramethyl- ethyle'ediami'e

(%), as catalyst, a'd potassim

persl&ate (F 2*

2E

A), as i'itiator, Gere

prchased &rom *i"ma ldrich (>*)# 3, 30

-methyle'oisacrylamide (B), ascrossli'!er, Gas otai'ed &rom Pharmacia

Biotech (>*)# %he acrylate salt (Fc) Gas

o- tai'ed y the 'etrali8atio' o&

acrylic acid Gith potassim

hydroH

ide#

%he sed rice hs! ori"i'ates &rom

camo/C, Bra8il# shes Gere prodced

thro"h calci'atio' i' a m&Me &r'ace at

temperatres ra'"i'" &rom 400 to D00 JC#

%he ashes, laeled as 9%(Ghere % is the

temperatre applied dri'" calci'atio'),

Gere pre- 7iosly "ro'd, a'd sie7ed

thro"h a 325 mesh (644 lm) sie7e prior

si'" i' hydro"el &ormatio'# ll reacta'ts

Gere o& a'alytical

"rade a'd Gere sed Githot

&rther priMcatio'#

2#2# Poly(acrylamide-co-acrylate)hydro"el &ormatio'

2#1 " o& m a'd 3#25 " o& Fc Gere added

to 30 mQ o& distilled Gater, led Gith

'itro"e' "as (to redce the i'hiiti'" e&&ect o&

the oHy"e' i' the radical polymeri8atio')#

&ter 10 mi', 16#2 m" o& F 2*

2E

A Gere added#

%hs, B (0#05, 0#1 a'd 0#2 mol-N related tothe amo't o& mo'omers) a'd 100 Q o&% soltio' 0#5 " Q-1

Gere also added# %he system Gas

mai'tai'ed 'der stirri'" a'd MoGi'"

'itro"e' 'til the hydro"el &ormatio' (p to

30 mi'), a&ter it Gas le&t to rest &or &rther 15

h at room temperatre# %he as-o-




6

6d*# C+'dido et al# / Composites: Part B 51 (2013) 246–253

2#4#3# *ca''i'" electro' microscopy copled

to e'er"y dispersi7e spectroscopy L-ray

(*–*)

%he morpholo"y o& the hydro"els (Gith

a'd Githot 9) Gas a'aly8ed thro"h

sca''i'" electro' microscopy copled to

'er"y ispersi7e L-ray *pectroscopy

(*–*/*himad8, model **

550) operati'" at 10 !e?# %he hydro"els Gere

immersed i' distilled Gater at room

temperatre 'til the eIilirim sGelli'"

has ee' reached (approHimately 24 h)# eHt,

the samples Gere remo7ed a'd immediately&ro8e' y immersio' i' liIid 'itro"e'#

%herea&- ter, the &ro8e' hydro"els Gere

&ractred a'd &ree8e-dried (Christ, lpha 1–2

Q Pls) at -55 JC &or 24 h# %he', the

hydro"els Gere "old-coated y sptteri'"

e&ore oser7atio' y *–*#

2#4#4#

%hermo"ra7imetry

(%.)%. Gas per&ormed i' a *imlta'eos

%hermal 'alysis *ys- tem, et8sch (odel

*% 40D P./4/. QHH) Gith a sca''i'" rate

o& 10 JC mi'-1 'der MoGi'" 2(")

at 20 mQ

mi'-1 i' a temperatre ra'"e &rom 22 to

1000 JC#

2#5# *tdy o& physical

properties

2#5#1# *Gelli'"

eHperime'ts

$'itially, the sGelli'" tests Gere employed

to determi'e Gater pta!e capacity o& the

materials# $' this Gay, 15 m" o& dried "els

Gere placed i' 30 mQ Mlter crciles

(porosity 'o# 0) pre-moist- e'ed a'd Gith a

dried oter Gall# %his set Gas i'serted i'

Gater i' sch a Gay that the "el Gas

completely smer"ed#%he crcile/hydro"el composite sample

sets Gere remo7ed at 7arios time i'ter7als,

Gith the eHter'al Gall o& the set dried a'd

the system Gei"hed# or each sample, 3

assays Gere per&ormed (' Y 3)# %he sGelli'"

capacity o& the hydro"el composites Gas

determi'ed y I# (1), Ghere KeI

is the

"ai'ed Gater mass (i' "rams) per "ram o&

composite hydro"el (asore't), m is the

mass o& the sGolle' asore't a'd m0 is the

mass o& the dry material U1,30V# %he !i'etics

o& sGelli'" i' each stdied medim Gas e7al-

ated# %he si8e distritio' o& the hydro"el

composites remai'ed i' the D–24 mesh

ra'"e#

tai'ed material Gas ct i' small pieces a'd

Gashed i' distilled Gater to remo7e 'o'-

reacted mo'omers# %he hydro"els Gere

o7e'-dried at 0 JC# %he si8e distritio' o& particles spreads &rom

K

eI

¼ ½mm0 !- 1 "1#

D to 24 mesh (2–0#1 mm)# %he

poly(acrylamide-co-acrylate)

hydro"el Gas laeled as PCZQ#

2#3# Poly(acrylamide-co-acrylate)/9-

hydro"el composite &ormatio'

%he poly(acrylamide-co-acrylate)/9

hydro"el composites Gere sy'thesi8ed as

descried to the same methodolo"y applied

to &orm the P-5-C0ZQ hydro"el# 9oGe7er ,

the mo'omers Gere dissol7ed i' a dispersio'

o& 9 otai'ed at di&&ere't calci'atio's

temperatre (10 Gt#N related to the total

amo't o& mo'omers)# %he hydro"el

composites Gere laeled as 09-.400, 09-.

500,

09-.600, 09-.

B00, 09-.

A00 a'd 09-.

D00

(Ghere the 'mer s- script is re&ere't to

the temperatre o& rice hs! calci'atio')#

2#4# Characteri8atio'




2#4#1# orier tra's&ormed i'&rared

spectroscopy (%$)

%he %$ spectra Gere otai'ed si'"

*himad8 %$-A300 eIipme't# %he dried

material Gas le'ded Gith FBr poGdera'd pressed i'to talets e&ore spectrm

acIisitio'#

2#4#2# Kide a'"le L-ray scatteri'" (KL*)

%he KL* proMles o& 9 a'd hydro"els

Gere otai'ed thro"h a poGder

di&&ractometer *himad8 model L 6000[

Gith C F a radiatio' sorce at 30 !? a'd 20

m#

2#5#2# %he e&&ect o& the io'ic stre'"th a'd type o&

metal io's o' the salt

%he hydro"els Gere immersed i' disti'ct

salt aIeos soltio's at di&&ere't

co'ce'tratio's (0#001, 0#01, 0#05 a'd 0#10 )a'd the sGelli'" capailities o& "els Gere

determi'ed thro"h the pre7i- osly

descried procedres U1,30V# aCl a'd

a9CE3

soltio's Gere sed &or stdyi'" the

a'io' e&&ect Ghile aCl a'd CaCl2 soltio's

Gere sed &or e7alati'" the catio' e&&ect o'

sGelli'" properties#

2#5#3# 7alatio' o& p9 e&&ect o' sGelli'"

capaility o& "els%he e&&ect o& the p9 o' the sGelli'" Gas

also 7eriMed i' &&er soltio's (p9s 2–12)#

%he procedres Gere the same as descried

ao7e# %he io'ic stre'"th o& the &&er

soltio's Gas !ept co'sta't ($ Y 0#1 )#

3# eslts a'd discssio'

3#1# 1%$0 a'd K-L* tech'iIes

%he %$ spectra o& 9 otai'ed at

di&&ere't temperatres are shoG' i' i"# 1a#

%he a'ds assi"'ed to the mai' 7iratio'al

modes o& *i $E $*i o'ds at 1100 cm-1 a'd

A00 cm-1 a'd 41 cm-1 ap- pear i' the spectra

i'depe'de't o' temperatre sed &or

calci'a- tio'# %hese a'ds are attrited

to the asymmetric a'd symmetric

stretchi'" a'd a'"lar de&ormatio',

respecti7ely U31–



33V# %he road a'd at 354A cm-1 is assi"'ed

to the 7ici'al sila'ol Gith hydro"e'-o'ded

Gater# %he i'te'sity o& a'd at 621 cm-1 ca'

e oser7ed o' spectra otai'ed &or

9 calci'ed at %P 00 JC a'd i'te'siMes

as the temperatre sed &or calci'atio's isi'creased# %his a'd is characteristic o&

crystalli'e cristoalita U34,35V# %he %$

spectra o& hydro"els &ormed si'" the ash

o- tai'ed at di&&ere't temperatres are

shoG' i' i"# 1 # %hese spectra shoG the

appeara'ce o& the a'ds at 1100, A00 a'd

41 cm-1, assi"'ed to *iE2

a'd *i $E $*i

o'ds U31–33V# rthermore, a Gea! a'd at 621 cm-1 ca' e oser7ed o' %$

spectra o& hydro"el o-tai'ed si'" ashes r't at %P 00 JC# %hs,

the prese'ce o& crystalli'e cristoalita

U6,34V i' hydro"el ca' e assi"'ed# $'

additio', the a'ds at 160 cm-1 a'd at

1564 cm-1, related to the C%E stretchi'"

a'd to the $E stretchi'", respecti7ely, de

to the &ormatio' o& copolymers# %hese

reslts i'dicate that copolymers a'd 9

compo'e't coeHisted i' sperasore't

hydro"els composites#%he KL* patter's o& 9 calci'ed at

di&&ere't temperatres &or 2 h a'd cooled to

room temperatre (Githi' the m&Me &or

24 h) are shoG' i' i"# 1c# *ch proMles

pro7ide i'&ormatio' rela- ti7e to the mai'

mi'eral co'stiti't a'd strctral

parameters o& 9# $t ca' e 'oticed &rom

KL* proMles that 9 calci'ed at di&-

&ere't temperatres prese'ted di&&ere't

strctres corroorati'" the %$ data# %he

ashes otai'ed at % \ 00 JC shoGed 'o deM

'ed di&&ractio' pea!s, t rather a'

amorphos halo that appears at ca#

2h Y 22J, Ghich i'dicates the ase'ce o&

crystalli'e domai's, ei'"

predomi'a't the 'o'-crystalli'e &orm o&

silica U13,35,36V# E' the other ha'd, 9

otai'ed at D00 JC shoGed pea!s o&

cristoalite, i'dicati'" that the material is

predomi'a'tly crystalli'e U6,34,3V#

%here&ore, is possile to i'&er that Ghe' the

rice hs! is calci'ed at hi"h temperatres

the reslti'" 9 prese'ts crystalli'e

strctre#

%he characteristics o& amorphos a'd

crystalli'e silica &rom 9 calci'ed i'

di&&ere't temperatre are mai'tai'ed i'

the hydro"el composites (i"# 1d) t the

di&&ractio' pea! assi"'ed to the crystalli'e

portio' is e'lar"ed de to the prese'ce o&copolymer# %he KL* patter's a'd %$

data e7ide'ce the &ormatio' o& the hydro"el

composite a'd s""est the prese'ce o& 9

i'to the polymer matriH, as s!etched i' i"#

2#

3#2# * copled to e'er"y dispersi7e L-ray

scatteri'" (*–*)

i"# 3 shoGs the * micro"raphs o&

&ree8e-dried hydro"el Mlled Gith rice hs!

ashes (9400, 09-

600 a'd 09-

D00) a&ter ei'"

sGelled at eIilirim# ll samples eHhiit

poros strctre characteristic o&

hydro"els, hoGe7er cha'"es i' strctre o&

material de to di&&ere't types o& ash

(crystalli'e or 'ot) ca' e e7ide'ced# or i'-

sta'ce, the micro"raph o& 09-.400

hydro"el

shoGs homo"e'eos poros distritio', t

a7era"e si8e smaller tha' those o& 09-.D00,

Ghile 09-.600

is i' a' i'termediate

co'ditio'# %his phe'ome'o' cold e

respo'sile &or the di&&ere'ce i' the

sperasore't properties amo'" 09-.D00,

09-.600

a'd 09-.400

composites# 6* tech-



i"# 1# (a) %$ spectra o& the 9 calci'ed i' di&&ere't temperatres[ () %$ spectra

o& the hydro"els composites[ (c) KL* patter's o& the 9 calci'ed i' di&&ere't

temperatres a'd (d) KL* patter's o& the hydro"els composite#



i"# 2# Proposed model &or the strctre o& hydro"el composite

'etGor! (particle si8e 644 lm)#

'iIe Gas tili8ed to e7alate the Mller

dispersio' i'to polymer matriHa'd the

possile eHiste'ce o& silicate particles

di&&sio' ot- Gard the hydro"el# *i"'al

relati7e o& silico' (&rom ashes) Gere e7i-

de'ced o' ima"es "e'erated y *

mappi'" tech'iIe, i'dicati'" the

homo"e'eos dispersio' o& *i i' Ghole

matriH#

3#3# %hermal

staility

%. a'd %. cr7es o& P-5-C0ZQ a'd

hydro"els composites (9.400, 09-.600 a'd

09-.D00

) Mlled Gith 10 Gt#N o& 9 calci'ed

at di&&ere't temperatres are shoG' a'd

compared i' i"# 4# %he decompositio' cr7e

o& P-5-C0ZQ a'd hydro"el composites

cold e di7ided i'to three steps# %he Mrst

sta"e is i' the ra'"e o& 50–200 JC de to a

loss o& moistre prese't i' the samples#

olloGi'", the Gei"ht losses Githi' the

temperatre o& 300–450 JC, Ghich are attrited to the

thermal decompositio' o& the caroHylate

a'd amide side-"rops o& the copolymers,

a'd also B moieties i' the 'etGor!,

leadi'" to the e7oltio' o& ammo'ia a'd

other "ases U3A,3DV# ri'" this period, the

o'sets o& the P-5-C0ZQ a'd hydro"elscomposites Mlled Gith 09-

400, 09-

600 a'd

09-D00

are similar a'd staility i'creases

Gith i'creas- i'" temperatre i' Ghich the

ashes Gere otai'ed, 3D1 JC (33#5N),

3A6 JC (31#4N), 3D5 JC (33#4N) a'd 405 JC

(33#3N), respecti7ely# %he third sta"e Gas

attrited to the rea!a"e o& copolymer

chai's, i' Ghich it Gas oser7ed a

displaceme't &or hi"her temperatres# $t ca'

e co'clded &rom %. data that the

temperatre i' Ghich the 9 Gas calci'ed

has a' i'Me'ce o' thermal staility o& cor-

respo'di'" sperasore't composites#

%he hydro"el 09-D00

cold e'ha'ce the

thermal staility to the hi"hest de"ree

amo'" the hydro"el samples i'7esti"ated#

%he properties o& 9 i' the sperasore't

composite polymeric 'etGor! may e the

mai'reaso's &or the di&&ere'ce i' %. reslt o& this system#



co'stite't chai's o& the matriH# *Gelli'" is

primarily de to the pe'etratio' o& Gater

i'to the hydrophilic polymer matriH y

capil- larity a'd di&&sio'# E' the other ha'd,

the sGelli'" rate o& a sperasore't is

si"'iMca'tly i'Me'ced y sGelli'" capacity,

si8e distritio' o& poGder particles, speciMc

sr&ace area, a'd appare't de'sity o&

polymer#

i"# 5a shoGs the !i'etics o& sGelli'" i'

distilled Gater o& 09-.400, 09-.

600 a'd

09-.D00

composites a'd P-5-C0ZQ# %he

oser7ed tre'ds i' the sGelli'" !i'etics o&

&or di&&ere't samples are 7ery similar# %he

de"ree o& sGelli'" i'creased Iic!ly dri'"

the Mrst 20 mi' o& immersio' &or all samplesa'd ca# D0N o& the sGelli'" eIilirim

7ale Gas reached i' this time ra'"e# %he',

a sloGer sGelli'" process too! place p to

the eIilirim (KeI

), aro'd 30 mi'# %he

KeI

7ales a'd the speed &or reach the

eIili- rim depe'd o' the "el &ormlatio'

(see the i'sertio' o' i"# 5a)# %he prese'ce

o& 9 "reatly impro7ed the Gater

asore'cy at eIilirim# Besides, 09-.D00

composites too! lo'"est time to reach

eIilirim# %he PCZQ hydro"el

prese'ted Gater asorptio' capacity at

eIilirim (KeI) o& 645 "

Gater /"

asore'tGhile

09-.400, 09-.

600 a'd 09-.

D00 composites

prese'ted hi"h- er Gater asorptio'

capailities o& A1, A02 a'd 10 "Gater

/"asro-

e't, respecti7ely#or e7alati'" the mecha'ism o& thesGelli'" process a'd the

temperatre e&&ect o& 9 ote'tio' o'

sGelli'" !i'etics o& the sperasore't

hydro"els composites, the seco'd order

sGelli'" !i'etics model U40,41V Gas adopted

to test the eHperime'tal data# %he seco'd

order sGelli'" !i'etic model ca' e

eHpressed as &olloGs:

tK ¼ - & Bt

"2#

Ghe

re

1-¼

! G2"3#

3#4# Fi'etics o& sGelli'"

%he sGelli'" process o& a hydro"el is

co'trolled y chemical a'd physical &orces as

Gell as y the co'seIe't elastic respo'se o&

the

s t

a'd

1GB ¼

t

"4#



i"# 3# * a'd * di&&racto"rams o& (a) 9.400

, () 9.600, a'd (c)

9.D00

hydro"els composites#

%he parameter correspo'ds to a'

i'itial sGelli'" rate U(dK/dt)0V o& the

hydro"el, ! s

is the co'sta't rate &or

sGelli'", Kt

is a theoretical sGelli'" 7ale

at eIilirim# Kt

a'd ! sGere calclated

y Mtti'" eHperime'tal data shoG' i'

i"# 5 to Is# (2)–(4) a'd the reslts are

"i7e' i' %ale 1# or all the strai"ht li'es,

the correlatio' coe&Mcie'ts (0 2) Gere hi"her

tha' 0#DDD, i'dicati'" that the sGelli'"

processes o& the sperasore'ts oey

the model tili8ed &or predict the

sGelli'"#%he sGelli'" rate co'sta't (!

s) &or 09-.

D00 –

Gas smaller tha' that o& P-5-C0ZQ#



ltho"h the i'trodctio' o& 09-D00

i'to

P-

CZQ 'etGor! "reatly impro7ed the

eIilirim Gater asor- e'cy, the

'ecessary time to reach the eIilirim Gas

hi"her leadi'" to a sloGer sGelli'" rate# %he

relatio'ship etGee' Gater pta!e

capaility a'd the temperatre applied &or

otai'i'" the 9 is shoG' i' i"# 6#

ccordi'" to the sGelli'" assays it is 7eriM

ed the 09-.D00

prese'ted hi"hest Gater

pta!e ecase 09-D00

has 7irtally 'o resi-

de# 09-D00

shoGed hi"h crystalli'ity de"ree

a'd the pre&erale i'tra-i'teractio's amo'"

its sila'ol "rops set &ree 'eG sites o' the

hydro"el matriH that cold i'teract to Gater

i'creasi'" their Gater pta!e capacity#



i"# 4# (a) %. a'd () %. cr7es o& PCZQ a'd hydro"els composites

(9.400, 9.

600a'd 9.

D00) Mlled Gith 10 Gt#N o& 9#

i"# 5# (a) e"ree o& sGelli'" a'd () plot o& t/K 7erss t as a

&'ctio' o& immersio' time#

%ale 1

&&ect o& temperatre o& otai'i'" the 9

sGelli'" !i'etics o& hydro"els composites&ormed#tteI

9ydro"el KeI

a K c

! s

d

PCZQ 645 ] 21 64D 24 ] 3 6#54 ' 10-

9.400

A1 ] 2 D1 12 ] 2 1#15 ' 10-

9.500

3 ] 25 AD 13 ] 4 1#D1 ' 10-

9.600

A02 ] 1D A00 10 ] 1 1#42 ' 10-

9.B00

D3D ] 24 D52 24 ] 4 2#4D ' 10-

9.A00

1031 ] 26 1056 2D ] 5 1#1D ' 10-

9.D00

10 ] 32 1124 35 ] 4 #40 ' 10-5

a Hperime'tal eIilirim sGelli'" ("Gater

/"asore't

)# %heoretical eIilirim sGelli'" ("

Gater /"

asore't)#

c Iilirim time (mi')#



d *Gelli'" rate co'sta't U("asore't

/"Gater

)/mi'V#

3#4#1# &&ect o& salt soltio' o' Gater

asore'cy

$t has ee' co'Mrmed, thro"h theoretical

a'd eHperime'tal co'sideratio's, that the

prese'ce o& io's has "reat e&&ect o' the

hydro"els sGelli'" eha7ior U42–44V# $' this

Gor!, the i'Me'ce o& io's i' the sGelli'"

capaility o& hydro"els Gas tested y the

additio' o& aCl (0#001–0#1 ) or

a9CE3

(0#1 ) or CaCl2

(0#1 ) i' the

hydro"el-srro'di'" soltio'#

i"# 6# &&ect o& temperatre &or otai'i'"the 9 i' the maHimm sGelli'" 7ale

(KeI) o& hydro"els composites#

%ale 2 prese'ts the data collected i'

sGelli'" measreme'ts &or the hydro"els i'

aCl soltio'# %he se'siti7ity o& hydro"el to



%ale 2

KeI("

Gater /"

asore't) as &'ctio' o& the io'ic &orce &or the hydro"els#

9ydro"el aCl (0#001 aCl (0#01 aCl (0#05 aCl (0#1

K K & K & K & K &

9.400

A1 ] 2 445 ] 6 0 24D ] 3 0 11A ] 2 0 A4 ] 1 0#A

9.600

A02 ] 1D 45D ] 4 0 253 ] 2 0 123 ] 2 0 A ] 1 0#A

9.D00 10 ] 32 63A ] 0 345 ] 4 0 16D ] 3 0 114 ] 2 0#A

PCZQ 645 ] 21 361 ] 4 0 1D5 ] 2 0 A5 ] 1 0 63 ] 1 0#D

prese'ce o& salts ca' e related y the dime'sio'less &actor & de- M

'ed as U45V:(

K sali'e

^

& ¼ 1-

K Gater

"5#

i' Ghich Ksali'e

a'd KGater

are, respecti7ely, the

sGelli'" capacity i' sali'e soltio' a'd i'

deio'i8ed Gater# ccordi'" to I# (5) the &

7ales ra'"e etGee' 1 a'd 8ero# s close the

7ale is o& 'it (1#0) hi"her is the se'siti7ity

o& hydro"el to the prese'ce o& salt# %he

opposite is 7alid: &or & eIal to 8ero the

hydro"el Gold 'ot pos- sess a'y se'siti7ity

to prese'ce o& salt# %he & 7ales (%ale 2) i'di-

cate that the hydro"el composites 'de"o

sli"htly less i'Me'ce to the prese'ce o& salt

tha' PCZQ#

%he i'crease i' the io'ic stre'"th redces

the di&&ere'ce i' the co'ce'tratio' o&mo7ale io's etGee' the polymer matriH

a'd the eHter'al soltio' (osmotic sGelli'"

pressre) a'd leads to a' immediate

co'tractio' o& hydro"el 'etGor!#

%he prese'ce o& di7ale't a'd tri7ale't

catio's i' sGelli'" soltio' drastically

redces the sGelli'" capacity o& the

hydro"els# %his is de to the compleHatio'

aility o& caroHymide or caroHylate "rops

a'd to the &ormatio' o& i'ter a'd

i'tramoleclar compleHes U46,4V# %he

hydro"el composites prese'ted "reater KeI

7ales i' sali'e soltio' (%ale 3) as

compared to P-5-C0ZQ o'e#3

oreo7er, ased o' KeI

7ales the

hydro"el composites Gere 'ot se'sile to

the type (a'd si8e) o& a'io', ecase the

7ales o& KeI

Gere similar &or Cl- a'd 9CE-

salt co'ter io's# ' a'alo"os oser7atio'Gas rece'tly reported &or poly(acrylamide-

co-acrylate) a'd celllose 'a'oGhis!ers

sperasore't composites U4AV#

3#4#2# Iilirim sGelli'" i' &&er

soltio's at 7arios p9

%he sGelli'" eha7ior o& P-5-C0ZQ a'd

composites (9.400, 09-.

600 a'd 09-.

D00)

at se7eral p9 co'ditio's Gas oser7ed Gith

the se o& &&er soltio's at p9s 2–12 at

co'sta't io'ic stre'"th (i"# )# ' i'crease

i' KeI

7ale Gas oser7ed as the p9 o& the

eHter'al soltio' is i'creased U4DV# $' acidic

medim, the caroHyl- ate a'io's are

proto'ated a'd the a'io'–a'io' replsi7e

&orces 7a'ishes[ this leads to a mi'imm

sGelli'" o& the hydro"el# s sGelled i' &&er Gith hi"her p9 7ales, the

caroHylate "rops o& hydro"els composites

ecome io'i8ed a'd the electrostatic

replsio' etGee' $CEE- "rops cases

eHpa'sio' o& matriH a'd, co'seIe'tly,

i'creases KeIU50V#

t p9 O 4 the hydro"el sGells mch morede to the replsio'

o& $CEE- "rops, Ghile at p9 2 the

hydro"el 'etGor! &ast col- lapses de to the

shieldi'" e&&ect &rom eHcess o& catio's# %he

hydro- "el 'a'ocomposites ased o'

starch-"-poly(sodim acrylate) matriH M

lled Gith celllose 'a'oGhis!ers stdied

y *pa"'ol

%ale 3



i"# # p9 e&&ect o' the de"ree o&

sGelli'"#

et al# U51V prese'ted similar respo'si7e

eha7ior i' relatio' to p9# %his eha7ior

ma!es the hydro"els composites stro'"

ca'di- dates to e tili8ed i' co'trolled

release systems# 9ydro"els Gith respo'ses to

7ariatio's o& p9 a'd temperatre ha7e ee'

eHte'- si7ely stdied Githi' the re&erred

class o& __smart materials`` Ghich ha7e ee'

applied i' GasteGater a'd i'dstrial e&M

e'ts, co'- trolled dr" release, separatio'

memra'es amo'" others U52–54V#

4#

Co'clsio

's

Poly(acrylamide-co-acrylate)/9 hidro"el

composites prese't- i'" rele7a't properties

Gere sccess&lly sy'thesi8ed, as oser7ed

y 1%$0 a'd KL* tech'iIes# 9

proceedi'" &rom rice hs! Gas calci'ed i'

di&&ere't temperatres &rom 400 to D00 JC#

KL* patter's shoGed that that 9

calci'ed at di&&ere't temperatres pre-

se'ted di&&ere't strctres co'Mrmi'" the

%$ data# %he ashes otai'ed at % 6 00 JC

shoGed 'o deM'ed di&&ractio' pea!s, i#e#,

prese'ts silica Gith certai' crystalli'ity# %his

stdy also e7alated the e&&ect o& crystalli'e

or amorphos 9 o' the Gater pta!e

capaility o& the hydro"el# %he prese'ce o&

09-D00

o' acrylamide–acrylate polymeric

matriH impro7ed the Gater-asorptio'

properties o& material, pro7idi'" a' i'creaseo& 6N i' the K

eI7al- es as compared to

hydro"el Githot 9 particles# %he 9 i'

crystalli'e &orm i'dces hi"her Gater pta!e

capacity (KeI) o& composites hydro"els de

to the i'tra-i'teractio's amo'" sila'ol

"rops o' 9 ma!e a7ailale 'eG sites i'

the polymer matriH, Ghich cold i'teract to

Gater# %he hydro"els composite poly(acryl-

amide-co-acrylate) Mlled Gith 9 pro7ed to

e adeIate &or the se as soil co'ditio'er#

%hese prelimi'ary reslts i'dicate that

KeI

("Gater /"

asore't

) as &'ctio' o& the

type o& a'io' a'd

catio'#

the hydro"els composites ha7e "reat pote'tial &or their tili8atio'i' the a"ro'omic area#



9ydro"el aCl a9CE3

Ca

KeI KeI & KeI & KeI &

9.400

A1 ] A5 ] 0# A3 ] 0# 26 ] 0

9.600

A02 ] A ] 0# D ] 0# 24 ] 0

9.D00

10 ] 114 ] 0# 11 ] 0# 3A ] 0

PCZQ 645 ] 21 63 ] 1 0#D1 6D ] 1 0#AD 1 ] 1 0#D

c!'oGled"eme'ts

%he athors Gold li!e to tha'! the M

'a'cial spport y >- CP (BP$ 02A0-

106/0A a'd P$Q – 13D#01#00/0D), y CPI

(Proc#

5030A/2010-) a'd to CECP->#





e&ere'ces

U1V Cha'drase!har *, Pramada P,

Pra7ee' Q# e7ieG processi'",

properties a'd applicatio's o& reacti7e

silica &rom rice hs! – a' o7er7ieG#

ater *ci

2003[3A:315D–6A#

U2V *ata ?, atrapita!!l C, Fiatti!omol

F# $'Me'ce o& po88ola' &rom 7arios

y- prodct materials o' mecha'ical

properties o& hi"h-stre'"th co'crete#

Co'str Bild ater 200[21:15AD–DA#

U3V %a'"chirapat K, Bra'asi'" ,

Chi'daprasirt P# $'Me'ce o& rice hs!–

ar! ash o' mecha'ical properties o&co'crete co'tai'i'" hi"h amo't o&

recycled a""re"ates# Co'str Bild

ater 200A[22:1A12–D#

U4V Cha'drase!har *, Pramada P,

Pra7ee' Q# &&ect o& or"a'ic acid

treatme't o' the properties o& rice hs!

silica# ater *ci 2005[40:6535–44#

U5V o8ai'ee , "o *P, *alema , %a'

F.# lidi8ed ed comstio' o& rice

hs! to prodce amorphos siliceos

ash# 'er" *st e7 200A[12:33–42#

U6V Prasetyo!o , amli W, 'dd *,

9amda' 9, *li!oGs!i B# Co'7ersio' o&

rice hs! ash to 8eolite eta# Kaste

a'a" 2006[26:113–D#UV Fordatos F, .a7ela *, t8io'i ,Pistiolas F, Fyritsi , i"opolo ?#

*y'thesis o& hi"hly siliceos W*-5

8eolite si'" silica &rom rice hs! ash#

icropor esopor ater200A[115:1AD–D6#

UAV *ri7asta7a ?C, all $, ishra $#

emo7al o& cadmim ($$) a'd 8i'c ($$)

metal io's &rom i'ary aIeos

soltio' y rice hs! ash# Colloid

*r&

200A[312:12–A4#

UDV *ri7asta7a ?C, all $, ishra $#

Competiti7e adsorptio' o& cadmim ($$)

a'd 'ic!el ($$) metal io's &rom aIeos

soltio' o'to rice hs! ash# Chem '"

Process 200D[4A:30–D#

U10V Whao P, .o L, Whe'" C# emo7al o&

eleme'tal mercry y iodi'e-modiMed

rice hs! ash sore'ts# '7iro' *ci

2010[22:1162D–36#

U11V ehdi , Iette , l amatty #

Per&orma'ce o& rice hs! ash prodced

si'" a 'eG tech'olo"y as a mi'eral

admiHtre i' co'crete# Cem Co'cr es

2003[33:1203–10#

U12V Qio %9# Preparatio' a'd

characteri8atio' o& 'a'o-strctred

silica &rom rice hs!# ater *ci '"

2004[364:313–23#U13V o'"mi' , Zpe'" ., Za'chao W,Ka'" W# "ree' rote to preparatio' o&

silica poGders Gith rice hs! asha'd Gaste "as# Chem '"

2010[162:50D–14#

U14V *iriGa'de'a *, $smail 9, $sha!ia! >*#

compariso' o& Ghite rice hs! ash

a'd silica as Mllers i' ethyle'e–

propyle'edie'e terpolymer

7lca'i8ates# Polym $'t2001[50:0–13#

U15V *ae-Ei P, a!dee C, %ha'mathor' P#

>se o& rice hs! ash as Mller i' 'atralrer 7lca'i8ates: i' compariso'

Gith other commercial Mllers# ppl

Polym *ci 2002[A3:24A5–D3#

U16V *ereda Q, Qope8-.o'8le8 ,

?isco'te QQZ, 'es C, rtado C.,

ia'de # $'Me'ce o& silica a'd lac!

rice hs! ash Mllers o' the di&&si7ity

a'd solility o& "ases i' silico'e

rers# Polymer 2003[44:30A5–D3#

U1V C+'dido *, Qeit;o C, icardo P*,

eitosa P, 'i8 C, odri"es 9#

9ydro"els composite o&

poly(acrylamide-co-acrylate) a'd rice

hs! ash# $# *y'thesis a'd

characteri8atio'# ppl Polym *ci

2012[123:AD–A#U1AV Cho F*, %sai C, Qo C%# %he asorptio'o& Co'"o red a'd 7acm pmp oil y

ice hs! ash# Bioresorce %ech'ol

2001[A:21–D#U1DV dam , Cha 9# %he adsorptio' o&

palmytic acid o' rice hs! ash



chemically modiMed Gith l($$$) io'

si'" the sol–"el tech'iIe# Colloid

$'ter&ace *ci

2004[2A0:55–61#

U20V a'e ?*, all $, *ri7asta7a ?C#

Fi'etic a'd eIilirim isotherm

stdies &or the adsorpti7e remo7al o&

Brillia't .ree' dye &rom aIeos

soltio' y rice hs! ash# '7iro'

a'a" 200[A4:3D0–400#

U21V Qa!shmi >, *ri7asta7a ?C, all $,

Qataye 9# ice hs! ash as a'

e&&ecti7e adsore't: e7alatio' o&

adsorpti7e characteristics &or $'di"o

Carmi'e dye# '7iro' a'a"

200D[D0:10–20#U22V *harma P, Far , Bas!ar C, Ch'"

K# emo7al o& methyle'e le &rom

aIeos Gaste si'" rice hs!

a'd rice hs! ash# esali'atio'

2010[25D:24D–5#

U23V Bchhol8 Q, .raham %# oder'

*perasore't Polymer %ech'olo"y,

eG

Zor![ 1DDA#

U24V a F, a P, oha' Z#

*y'thesis o& sperasore't

copolymers as Gater ma'a"eale

materials# Polym $'t 2003[52:6A–2#

U25V l-rehim 9, 9e"a8y , l-mohdy

9Q# adiatio' sy'thesis o& hydro"els

to e'ha'ce sa'dy soils Gater rete'tio'

a'd i'crease pla't per&orma'ce# ppl

Polym *ci 2004[D3:1360–1#

U26V o!hade P, Patil *, mi'aha7i %#*y'thesis a'd characteri8atio' o& semi-

i'terpe'etrati'" polymer 'etGor!

microspheres o& acrylamide "ra&ted

deHtra' a'd chitosa' &or co'trolled

release o& acyclo7ir# Carohyd Polym

200[6:605–13#

U2V Lia Z<, .o %Z, Wha'" B9, Wha'" BQ#

9emo"loi' reco"'itio' y impri'ti'"

i' semi-i'terpe'etrati'" polymer

'etGor! hydro"el ased o'

polyacrylamide a'd chitosa'#

Biomacromolecles 2005[6:2601–6#



U2AV 9ill # lectric-Meld-e'ha'ced

tra'sport i' polyacrylamide

hydro"el 'a'ocomposites# Colloid

$'ter&ace *ci 200[316:635–44#U2DV Bapai F, .iri # *Gelli'" dy'amicso& a macromoleclar hydrophilic 'etGor!

a'd e7alatio' o& its pote'tial &or

co'trolled release o& a"rochemicals#

eact

'ct Polym 2002[53:125–41#

U30V Wha'" Q, a!oto'drada'y , yles ,

e''iri 9, Kester %# r"i'i'e-"lyci'e-

aspartic acid modiMed rosette

'a'ote–hydro"el composites &or

o'e tisse e'"i'eeri'"# Biomaterials

200D[30:130D–20#

U31V Falapathy >, Proctor *, *hlt8 # 'impro7ed method &or prodctio' o&

silica &rom rice hll ash# Bioresor

%ech'ol 2002[A5:2A5–D#

U32V ella ?P, Fh' $, 9ot8a #

Characteri8atio' o& rice hs! ash &or

se as raG material i' the

ma'&actre o& silica re&ractory# <=mic

o7a 2001[24:A–A2#U33V 9e"de , ao ?# Er"a'ic modiM

catio' o& %E* ased silica aero"els si'"

heHadecyltrimethoHysila'e as a

hydrophoic rea"e't# ppl *r& *ci

2006[253:1566–2#

U34V %aa! , &si' B, Ca"lar B, Fo!sal #

Characteri8atio' a'd pillari'" o& a

%r!ish e'to'ite (esadiye)# Colloid

$'ter&ace *ci 200[313:5–11#

U35V air ., adadish F*, raai #

eacti7e po88ola'as &rom rice hs!

ash: a' alter'ati7e to ceme't &or rralhosi'"# Cem Co'cr es

2006[36:1062–1#U36V .e'ie7a *, %rma'o7a *C,

imitro7a *, ?lae7 Q%# Characteri8atio' o&rice

hs!s a'd the prodcts o& its

thermal de"radatio' i' air or

'itro"e' atmosphere# %herm 'al

Calorim 200A[D3:3A–D6#

U3V Frish'arao ?, *rahma'yam ,

Fmar %# *tdies o' the &ormatio' o& lac! particles i' rice hs! ash# r

Ceram *oc 2001[21:DD–104#

U3AV Wha'" , Ka'" # *tdy o'sperasore't composites# $L:

sy'thesis,

characteri8atio' a'd sGelli'"

eha7iors o& polyacrylamide/clay

composites ased o' 7arios clays#

eact 'ct Polym 200[6:3–45#

U3DV * L, Wha'" ., L F, Ka'" , *o'" C,Ka'" P# %he e&&ect o& %/modiMed

% o' the strctre a'd

per&orma'ce o& the sperasore't

composite# Polym Bll 200A[60:6D–A#

U40V Farada" , >8m EB, *araydi' #

Kater pta!e i' chemically crossli'!ed

poly(acrylamide-co-croto'ic acid)

hydro"els# ater es 2005[26:265–0#

U41V Qi , Ka'" K, Ka'" # *y'thesis,

characteri8atio', a'd sGelli'" eha7iors

o& chitosa'-"-poly(acrylic

acid)/poly(7i'yl alcohol) semi-$P

sperasore't hydro"els# Polym d7

%ech'ol 200D[22:62–34#

U42V lliott , acdo'ald , ie ,

BoGma' C# *trctre a'd sGelli'"

o& poly(acrylic acid) hydro"els: e&&ect o&

p9, io'ic stre'"th, a'd diltio' o'

the crossli'!ed polymer strctre#Polymer 2004[45:1503–10#

U43V Wha'" , %a'" , BoGyer , ise'thal

, 9le # 'o7el p9- a'd io'ic-

stre'"th-se'siti7e caroHy methyl

deHtra' hydro"el# Biomaterials

2005[26:46–A3#

U44V Qi 9<, Whe' , K 9# $o'ic-

stre'"th- a'd p9-respo'si7e

polyUacrylamide- co-(maleic acid)Vhydro"el 'a'oMers# acromol

Chem Phys200[20A:A4–A0#

U45V Pora7adi , *ade"hi ,

9osei'8adeh 9# odiMed carra"ee'a'#

5# Preparatio', sGelli'" eha7ior, salt-

a'd p9-se'siti7ity o& partially

hydroly8ed crossli'!ed carra"ee'a'-

"ra&t-polymethacrylamide

sperasore't hydro"el# Polym d7%ech'ol 2004[15:645–55#

U46V ahda7i'ia ., Wohriaa'-ehr ,



Pora7adi # odiMed chitosa' $$$,

sperasore'cy, salt- a'd p9-

se'siti7ity o& smart ampholytic

hydro"els &rom chitosa'-"-P# Polym

d7 %ech'ol 2004[15:13–A0#

U4V Ka'" , Whe'" Z, Wha'" # *tdy o'

sperasore't composite L?$#

*y'thesis, characteri8atio' a'd

sGelli'" eha7iors o& poly(sodim

acrylate)/7ermiclite sperasore't

composites# r Polym

200[43:16D1–A#

U4AV *pa"'ol C, odri"es 9, eto

.?C, Pereira .B, aardo ,

ado7a'o7ic , et al# a'ocomposites

ased o' poly(acrylamide-co-acrylate)a'd celllose 'a'oGhis!ers# r Polym

2012[4A:454–63#

U4DV *pa"'ol C, odri"es 9, Pereira

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U51V *pa"'ol C, odri"es 9, Pereira

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200[56:150–#

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Documents

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