Cellulo acetate butyrate as multifunctional additive for poly(butylene succinate)by melt blending:Mechanical
properties,biomass carbon ratio,and control of biodegradability
Yuya Tachibana a ,Nguyen Thien Truong Giang a ,b ,Fumi Ninomiya a ,Masahiro Funabashi a ,Masao Kunioka a ,*
a National Institute of Advanced Industrial Science and Technology (AIST)/1-1-1Higashi,Tsukuba,Ibaraki 305-8565,Japan b
National Institute of Animal Husbandry (NIAH)/Tu Liem District,Hanoi,Socialist Republic of Viet Nam
a r t i c l e i n f o
Article history:
Received 14December 2009Received in revid form 7January 2010
Accepted 8January 2010
Available online 22January 2010Keywords:
Poly(butylene succinate)Cellulo acetate butyrate Plasticizer
霍建华女友Biomass carbon ratio Biodegradability
a b s t r a c t
We have evaluated the plasticizing effect of poly(butylene succinate)(PBS)and cellulo acetate butyrate (CAB).PBS and CAB were mixed with a melt-kneading machine.The tensile strength and strain at break in the ca of the blend with 10%CAB in the PBS matrix were 547%and 35MPa.It showed that CAB acted as a plasticizer for PBS.The biomass carbon ratio of the blends measured by accelerator mass spec-trometry bad on ASTM D6866showed that the biomass carbon derived from a part of the CAB cor-responded to the theoretical value of the polymer blend.The biodegradation of PBS with the CAB melt blend powders was evaluated by a microbial oxidative degradation analyzer under controlled compost conditions bad on ISO 14855-2.PBS with 10%CAB was not degraded within 60days due to the addition of CAB that could control the biodegradability of the PBS.
Ó2010Published by Elvier Ltd.
1.Introduction
Aliphatic polyesters,such as poly(lactic acid),polycaprolactone,and poly(butylene succinate)(PBS),have received signi ficant interest for industrial applications,such as agricultural mulch sheets to protect against incts,control growing weeds and maintain suitable conditions,such as temperature and moisture,for the better growth and effective production of vegetables [1,2].It is important to control and inhibit the biodegradability during u,therefore chemical modi fication,the addition of a stabilizer,and polymer composites were employed.Furthermore,the flexibility of the material is an important property for end-u applications.The biodegradability of materials is also uful for the solution of waste problems,thus biodegradable materials are called environment friendly polymers.
PBS resins are commercially available biodegradable materials [3,4].One of the is available under the tradename “Bionolle Ò”bad on the polycondensation of 1,4-butanediol and succinic acid by a Japane company (Fig.1.)[5].However,other properties of PBS,such as softness,tensile and gas barrier properties,melt
viscosity for further processing,etc.,are frequently insuf ficient for various end-u applications.To mo
dify its properties,some methods such as an additive,inorganic filler,nanocomposite,and other polymer were developed [6].In addition to its biodegrad-ability,PBS has recently been produced from biorenewable resources to reduce greenhou gas emissions and provide sustainable alternatives to the reliance on limited petroleum-bad resources.The Showa High Polymer Co.[7]and Mitsubishi Co.[8,9]are now also establishing the production of succinic acid as one of the monomers of PBS from biomass resources,and a partially-biobad PBS is produced.We developed a fully biobad PBS from the biobad furfural [10].To promote high biobad materials,it should be required to u the additives derived from renewable materials.
Cellulo esters are one of the thermoplastics derived from biomass feedstocks.Cellulo acetate butyrate (CAB)esteri fied by acetyl and butyryl groups (Fig.1.)is a brittle and transparent material.Therefore,CAB has been ud as a photo film and a coating material.Some rearchers reported that CAB acted as a plasticizer for some polyesters,such as poly(hydroxy butyrate)[11e 13].We reported that biobad furfural was a good plasticizer for PBS [14].Ogata et al.produced the cast film of CAB which contained PBS as a plasticizer [15].The CAB cast films containing PBS obtained using
*Corresponding author.Tel.:þ81298614584;fax:þ81298614589.E-mail address:m.jp
(M.
Kunioka).Contents lists available at ScienceDirect
Polymer Degradation and Stability
journal h omepage:ww w.elvi
0141-3910/$e e front matter Ó2010Published by Elvier Ltd.doi:10.1016/j.polymdegradstab.2010.01.006
Polymer Degradation and Stability 95(2010)1406e 1413
the cast-blend method were transparent and elastic materials,and the Young's modulus of the CAB/PBS blendfilms decread as the ratio of PBS incread to40%becau of the plasticizing effect of the PBS.On the other hand,we have ud CAB as an additive derived from biomass feedstocks for PBS prepared by melt-pressing with a dry blend[16].The strain at break was over270%with the addition of20%CAB,however,it emed that the melt-pressing ud as the molding method is insufficient to prepare a homoge-neous blend sample.
Furthermore,the cellulo moiety of CAB is derived from biomass feedstocks,and the PBS/CAB blends become partially-biobad materials with the CAB ratio.When the product is ud as a biobad material,it is important to measure the biomass carbon ratio.Recently,the accelerator mass spectroscopy(AMS)(Fig.2) measurement method for determining the biomass carbon ratio bad on the American Society for Testing and Materials(ASTM) D6866method entitled“Standard test methods
铁军公园今生共相伴for determining the biomass carbon ratio of solid,liquid,and gaous samples using radiocarbon analysis”has become very important in thefield of biomass plastics[3,17e21].The AMS method has been ud for the carbon dating of archaeological and geological samples.In addition, the method can be applied to a mass balance study using a lower amount of14C-labelled metabolic compounds for biological systems.AMS can measure very small14C concentrations,and determine the ratio of the radiocarbon-14to carbon-12and13.The ratio14C/12C in biomass carbon is around1Â10À12.Fossil resources and materials are tho that contain no14C becau all the14C atoms that have a5730year half-life time had been changed to14N during their very long burial time.
As mentioned above,the biodegradability is the most charac-teristic and important property of PBS.The biodegradability of a polymer blend often changes from the original polymer depending on the composition.To evaluate the biodegradability of plastics,some international standard measurement methods have been t such as the International Organization for Standard(ISO) 14851,ISO14852,ISO14855-1,ISO14855-2,ISO14853,and ISO 15985.The ISO14855-2as shown in Fig.3is the ultimate aerobic biodegradability of plastic materials under controlled compost conditions using the Microbial Oxidative Degradation Analyzer (MODA)apparatus[3,22,23].
In this paper,we mixed PBS and CAB by melt-kneading and measured its chemical properties,therm
al property,and mechanical properties.The variation in the biomass carbon contents as the ratio of CAB incread and the effect of the CAB on the biodegradability of the PBS were evaluated.
2.Experimental
2.1.Materials
PBS,extended with1,6-diisocyanatohexane(Mn¼5.0Â105, Mw/Mn¼2.7)and CAB(Mn¼1.1Â105,Mw/Mn¼2.8),were purchad from the Aldrich Chemical Co.All materials were ud after drying at80 C for24h in vacuo.
2.2.Melt-kneading of PBS/CAB
PBS and CAB(ca.10g)were melt-kneaded using a kneading machine(Imoto Seisakusho,Co.,Ltd.;Micro melt-kneader)at the rotation rate of30rpm and220 C for15min.The mixing part (43.0mm length and19.4mm radius)is a cylinder with a rotating piston.The mixing mechanism is the Weisnberg effect generated by the surface of the piston and the melting blend resin.The mixed blends were compresd to a100Â100Â0.5mm sheet at20MPa using a hot-pressing machine(Tester Sangyo Co.,Ltd.;SA-303)at various temperatures for5min.After compressing,the melt-presdfilms were gradually cooled to room temperature.After cooling,the sheets were cut into dumbbell-shaped
specimens
Fig.2.Outline of the accelerator mass spectroscopy(AMS)apparatus(size ca.15Â10m,height2m)for de
termining the percentage of modern carbon(pMC)by the ratio of14C/12C (14As)at the Institute of Accelerator Analysis,Ltd.,
Japan.
Fig.1.Molecular structure of poly(butylene succinate)(PBS)and cellulo acetate
butyrate(CAB).
Y.Tachibana et al./Polymer Degradation and Stability95(2010)1406e14131407
(100mm total length,25mm total width,5mm narrow width, 0.5mm thick,and25mm effective distance
between chalks)bad on ISO527-type5(JIS K7127-3).
2.3.Chemical and thermal properties
内毒The IR spectrum was measured by an FT-IR(Thermo Scientific; Nicolet6700)equipped with a single reflection ATR system (Thermo Scientific;SMART iTR).The molecular weight was deter-mined by gel permeation chromatography(GPC)using a GPC system(Tosoh Co.,HLC-8320GPC)with a refractive index detector and a combination of two columns(Tosoh Co.,TSK GMHXL).The columns were eluted with chloroform(flow rate of1mL/min at 40 C)and the molecular weights were calibrated with polystyrene standards.The melting temperature was determined by a differ-ential scanning calorimeter system(Seiko Instruments Inc.,Japan; SSC/5520).After the sample was heated to220 C and cooled to 30 C at the rate of10 C/min,it was heated from30 C to220 C at the rate of10 C/min as the cond heating scan.The melting temperature of the PBS/CAB blend was measured for the cond heating scan.
2.4.Mechanical properties
The tensile strength and strain at break of the PBS/CAB blend were measured using tensile tests.The tensile tests bad on ISO 527-3(JIS K7127-3)were carried out using a universal material t
esting machine(Shimadzu Co.;Autograph AG-1000B)with the dumbbell-shaped specimens at room temperature.The grip distance was50mm,the gage length was25mm,and the tensile test speed rate was5mm/min.The tensile strength was determined as the ultimate strength required to break the materials on the stress e strain curve.The tensile strain at break was determined to be the maximum strain of the stress e strain curve.An average value was taken from the measurements of three samples under the same conditions for each blend specimen.
2.5.Sample preparation for measurement of biomasss carbon ratio
The sample preparation and measurement were performed at the Institute of Accelerator Analysis,Ltd.(IAA),Japan.All carbon atoms in the blend samples were transferred to graphite carbons through rial oxidation and reduction reactions using a quartz glass tube and a vacuum manifold system.The blend(6.5mg)was mixed with CuO(1g)and transferred to a quartz glass tube.The tube was clod after storage under vacuum for10h.The blend sample in the tube was oxidized to CO2at500 C for30min and at 850 C for2h.Subquently,CO2,CO,and H2O were cold-trapped into another tube using dry ice-ethanol(À76 C)connected in the clod vacuum line system.The cold-trap step was repeated twice. Only pure CO2was cold-trapped in a quartz glass tube with pure ferrous powder in liquid nitrogen(À196 C)from the reactants such as CO2,CO,and H2O in another tube unde
哥白尼怎么死的r dry ice-ethanol.The CO2 with ferrous powder was reduced to graphite at650 C for10h. After the process,the pure graphite with oxidized iron(1mg) was then transferred to a sample holder(small rod shape;1mm hole).
2.6.Biomass carbon ratios bad on ASTM D6866
The measurement of the ratio of the three carbon isotopes(14C, 13C,and12C)using AMS was performed at the IAA.The
AMS
Absorption column of carbon dioxide
Dehumidifying trap 2
Dehumidifying trap 1
Absorption column of water
CaCl2
CaCl2
SiO2
SiO2
Ammonia trap
2N H2SO4
Heater
Mixture of compost, test
material and a sand
Reaction vesl
Humidifier
Water
Carbon dioxide trap
NaOH (Soda lime)
Outlet
Thermo nsor
Compresd air
Carbon dioxide trap system
NaOH+Ca(OH)
2
(Soda lime/Soda talc)
Fig.3.Biodegradation evaluation method by gravimetric measurement of carbon dioxide evolved in laboratory-scale test using Microbial Oxidative Degradation Analyzer(MODA) instrument in controlled compost at58 C bad on ISO14855-2.
Y.Tachibana et al./Polymer Degradation and Stability95(2010)1406e1413
1408
measurement procedure is outlined in Fig.2.Our measurements were obtained using the3MV tandem accelerator system at the IAA.The carbon in the graphite,transferred from the blend samples,was ionized using a cesium cation beam.The reduced carbon atoms were accelerated using a3MV tandem accelerator (NEC Pelletron,9SDH-2).The amounts of12C and13C were detecte
d as a current using multi-Faraday cups.The14C atoms were detected using a gas detector.The percent modern carbon(pMC)was calculated from the ratio of the14C to12C concentrations for the blend sample.The percentage of modern carbon(pMC)for an oil-bad carbon is0%.The pMC for the biomass made from thefixa-tion of CO2in the modern atmosphere through photosynthesis is 108e110%in2002.The biomass carbon ratio was determined from the14C concentration measured using AMS bad on the ASTM D6866standard method.The reference material was measured for the obtained graphite using AMS.The biomass carbon ratios were calculated as follows:
14As¼14C=12C in sample(1) 14Ar¼14C=12C in reference materialðNIST SRM4990cÞ(2) D14C¼½ð14AsÀ14ArÞ=14Ar Â1000ð&Þ(3) pMC¼D14C=10þ100ð%Þ(4)
Biomass carbon ratio¼0:93ÂpMCð%Þ(5) D14C is the isotope differential ratio of14C of the sample and reference material,and pMC is the percentage of modern carbon. Modern carbon bad oxalic acid radiocarbon[Standard Reference material(SRM)4990c,NIST,USA]was ud as the reference material.The pMC of the all biomass compounds was around110% in2002.The pMC can be slightly higher than100%becau of the continuing,but diminishing effects of the1950s nuclear testing programs.During this period,large amounts of14C were ejected into the atmosphere.Becau all the sample14C is referenced to a“prebomb”standard,all pMC values must be multiplied by0.93to correct
for the bomb carbon and to obtain the true biomass carbon ratio of the sample as indicated in eq.(5)bad on ASTM D6866.
2.7.Biodegradation measurement bad on ISO14855-2
The PBS/CAB solid blend with dry ice was mechanically crushed by a rotating mixer with titanium blades.The crushing was carried out15times for3min each.After drying under reduced pressure at room temperature,the sample powder was parated using sieves of120mesh(125m m)and60mesh(250m m).Standard sieves with a guarantee were ud.The powders,which pasd through a60mesh sieve and held on the120mesh,were employed as the powder samples.The sieves with the crude polymer powders were t on a sieve vibrator and vibrated for15min.A biodegradation test was performed using the Microbial Oxidative Degradation Analyzer(MODA)apparatus in controlled compost at58 C as shown in Fig.3.The controlled compost(YK-6,Hissan Trading Co., Ltd.,Japan)for the MODA bad on ISO14855-2was prepared as follows.The waste material of ud wood blocks for growing mushrooms and chicken droppings was composted for ven months.During this period,a mature compost was prepared.After preparation,this obtained compost was sieved using a4.7mesh (4mm),kept at room temperature and prevented from drying. Before using this compost,an activation step(preincubation)was required to recover the biological activities f
or the respiration and biodegradation by the microorganisms.The controlled compost prepared by mixing144g of compost(60g total dry solids)and 320g of a sand,and its water content was controlled to over 80wt%(the weight of the volatile solids of this compost without a sand).This amount was for one reaction vesl.Preincubation was done once for the total amount of blanks and samples using a large container(5L).Sea sand was added to create good homo-geneous conditions and a better aerobic environment inside the compost.This compost for the activation step was mixed once
a day,and the water content was adjusted to65wt%for7days at
58 C.A10g sample was well mixed in the activated compost with a sand(ca.400g)and transferred to a reaction vesl.Compost with no sample was ud as the blank to determine the respiration activity of this compost.The biodegradation tests were performed at58 C and a10mL/min air(CO2-free)flow rate for60days.The activated compost ud in this study produced50mg CO2per gram of volatile solids of this compost over thefirst10days.In almost all cas,the number of experimental replicates of the blank or sample was two(duplicate).The produced CO2amounts were measured once a day by measuring the weights of an absorption column for carbon dioxide and an absorption column for water.The degree of biodegradation percentage was calculated from the produced CO2 a
mount from which was subtracted the respiration CO2amount determined from a blank,and the theoretically produced CO2 amount of the added sample.For example,10g of PBS could be changed into20.47g of CO2which was the theoretical amount for the100%biodegradation.As recommended by ISO14855-2,once a week,the sample and compost were well mixed and the water content was controlled.The absorbed CO2amounts for the absorption columns reached40%of the theoretical absorption capacity,and the chemicals(soda lime and soda talc)inside the columns were changed.This test method is bad on ISO14855-2.
3.Results and discussion
3.1.Preparation of PBS blend with CAB by melt-kneading
In general,the properties of the polymer blend were signifi-cantly influenced by the mixing process conditions.The melt-kneading,which was the mixing process by melting over the melting temperature of the materials and mixing by the shear stress was employed in this study for preparing the homogeneous blend of PBS and CAB.The melting temperature of PBS ud in this study was118 C,and CAB had no melting temperature.The aspects of the blends depended on the blending condition are shown in
Table1
Aspect of PBS/CAB blends.a
PBS/%CAB/%Temp/o C Transparency Color Shape
9010160translucent white lf-standing 9010180translucent white lf-standing 9010200translucent white lf-standing 9010220translucent pale yellow lf-standing 9010240translucent blown lf-standing 9010260translucent dark blown lf-standing 1000220translucent white lf-standing 955220translucent white lf-standing 8020220translucent pale yellow lf-standing 7030220translucent pale yellow lf-standing 6040220transparent pale yellow lf-standing 5050220transparent brown soft
4060220transparent brown soft
3070220transparent brown soft
2080220transparent pale yellow brittle 1090220transparent pale yellow brittle
0100220transparent pale yellow brittle
a PBS and CAB(ca.10g)were melt-kneaded at rotation rate of30rpm for15min.
缺字开头的成语Y.Tachibana et al./Polymer Degradation and Stability95(2010)1406e14131409
Table 1.The tansparency,color,and shape were estimated from the appearance.Self-standing means that the blended film could stand without any other supports,soft means that the blended film could not stand by itlf,and brittle means that the specimen could not be molded.When the melt-kneading temperature of the PBS and CAB is under 160 C,which is higher than the melting temperature of PBS,and the softening temperature of CAB,PBS and CAB had not been miscible,a heterogeneous blend was produced.The thermal degradation temperature of CAB or PBS for a 5%weight loss was over 300 C measured by thermogravimetric analysis.Therefore,the melt-kneading was carried out from 160 C up to 260 C.However,the resulting blends became dark in color with the increa in the temperature and the kneading time.For the blend including CAB,an unusual odor was produced during the melt-kneading.As the odor might be butyric acid,it suggested that the ester group of CAB was decompod during the melt-kneading.On the other hand,no decomposition was obrved in the thermog-ravimetric analysis of the PBS/CAB blend samples.Therefore,a small amount of CAB had decompod due to the heating and shear stress.The PBS/CAB film was molded by a hot-pressing method.It ems that the resulting films were fully miscible,becau no heterogeneous part
was obrved in the film by visual judgment.The films became transparent with the CAB increa due to the effect of the CAB which was a transparent material.Although the blends with any ratio of CAB could be molded,the blend in which the ratio of CAB was over 80%could not be cut into speci-mens for measurement of its mechanical properties due to its brittleness.
3.2.Stability of PBS/CAB blend during melt-kneading
The number averaged molecular weight (Mn)and molecular weight distribution (Mw/Mn)of the melt-kneading blends of PBS/CAB (¼90/10(wt/wt))for 15min at various melt temperatures are shown in Fig.4.The Mn and Mw/Mn of the original PBS were 5.0Â105and 2.7,and tho of the original CAB were 1.1Â105and 2.8,respectively.The fact that the molecular weight decread with the increasing temperature and finally down to 2.1Â105at 260 C suggests thermal degradation of PBS or CAB in the blends.The Mn and Mw/Mn of the melt-kneading blends of various CAB ratios for 15min at 220 C are shown in Fig.5.The Mn linearly decread with the CAB increa and the Mw/Mn was maximized at 50%CAB.This phenomenon showed the increa in CAB,which had a lower molecular weight than that of PBS,and the mixing of the materials which had different molecular weights.The decomposition
depending on the CAB ratio did not occur bad on the obrvations.
The IR spectra of the PBS/CAB blends are shown in Fig.6.The peaks of the blends of the PBS/CAB samples with various ratios were the mixed peaks of PBS and CAB in proportion to the ratio
and
Temperature / °C
Mw/Mn
未来的反义词M n x 10-5
Fig. 4.The number averaged molecular weight (Mn)(C )and molecular weight distribution (Mw/Mn)(:)of PBS/CAB (9/1)melt-kneaded at various temperature for 15
min.
六年级上册寒假作业答案Ratio of CAB / %
Mw/Mn
M n x 10-5
Fig.5.The Mn (C )and Mw/Mn (:)of PBS/CAB blends melt-kneaded with various ratio of CAB at 220 C for 15min.The Mn and Mw/Mn of the original PBS are 5.0Â105and 2.7,and tho of original CAB were 1.1Â105and 2.8,respectively.
3000200015001000
Wavenumbers /cm -1
PBS/CAB
-1
Fig.6.IR spectra of PBS/CAB blend by melt blended at 220 C for 15min.
Y.Tachibana et al./Polymer Degradation and Stability 95(2010)1406e 1413
1410
