CA2067229A1 - Biodegradable polymeric materials and articles fabricated therefrom - Google Patents

Abstract

2067229 9106601 PCTABS00005 A composition comprising one or more polymers and a filler which comprises one or more degradation enhancing materials which enhance the biodegradation of the polymers in association with one or more biodegradable safening materials which inhibit the enhancing activity of the enhancing materials whereby on biodegradation of the safening materials the activity is completely or partially restored.

Description

2 ~ _ ~ r ~ ,.~ 9 wosl/o66ol PCT/US90/06363 --1-- .

~ .
BACK ROUND OF THE INVENTION
1. Field of the Invention . _ _ _ This invention relates to biodegradable polymeric compositions.and to articles fabricated therefrom. More particularly, this invention relates to such composit ions ' which exhibit improved biodegradabili~y when exposed to environmental effects such as sunligh~, heat, water, oxygen, pollutants, microorganisms, insects, animals and mechanical forces such as wind and rain.

2. Prior Art - ' . 15Many discardable packaging items such as bags and : containers are destined, a~er a relatively short~
functional life to arrive as a significant component of urban garbage. .Because-of the increased use of.plastics in the fabrication of these discardable packing materials, i~ has been proposed to make throwaway materials from biodegradable plastics to ameliorate waste disposal problems. "'' owever,:the low-cost~high volumne packagingici .
'' materials such'as;polyethylene,:polypeopylene, polys~yrene 25~'and poly(ethylene terephthalate):are~not natura'lly ' biodegradable~ ~Severàl methods have been proposed to ' enhance'the'biodegradabi:lity of such polymeric materials and/vr to develop other useful buodegradable polymeric materials. For example, U.S. Patent No. 4,016,111 ;30 discloses~that;compo'sitions.'~'Qf~e~hylene acrylic acid copolymer and a starchy material are biodegeadable. U~'S.
a't'ent'iNo.'-4,'337,181~~describes~a:.biodegradable composition ''''~contaLning 'up'`to''abo'ut:60%'"gelatinized:starchTand:.various le'v'els ~f'êt'hyle'nè"~'a'c`ryl^ic'acid:copolymer-.cand~-opt.ionally polye~hy^lenei.~''3U.'S¢'~Patent:'No~ 4,016,'117 describes a '`.
biodegradable composition which comprises-.a:synthetic^~"
resin, a b'iodegr'a'dable granular filler~such-as natural . . - . ::
.,. ' .~.
` :-w~gl/~66ia~ 3 -2- PCT/US9Q/06363 starch, and a substance which is autooxidizable to yield a peroxide which attacks the carbon to carbon linkages of the resin. PCT Appln. WO 8B/09354 describes a degradable polymer composition which is a blend of a normally stable chemically saturated polymer such as polyethylene, a less stable chemically unsaturated polymer or copolymer such as a styrene/butadiene block copolymer, or natural rubber, an anti-oxidant active over a limited period and a latent pro-oxidant such as an organic salt of a transition metal, e.g. cobalt naphthenate, which may optionally.include filler particles of a directly biologically sensitive material such as a natural starch, a derivative of natural starch, a natural protein, a natural cellulose or a sugar.
Previous efforts to make non-biodegradable polymers biodegradable by blending them with biodegradable fillers and other additives have not been successful. Existing biodegradable plastics are deficient.in properties required in most packaging applications and are more expensive than commonly used packaging plastics.
~urthermore, such materials often fail to degrade in a reasonable period of time to the point where they lose their structural integrity and fall apart. This loss in physical~iproperties,~l,embrittlement.and disintegration are .required in-order~to lessen the volume of such articles in landfills, or;to allow.release of the conten~s of the 25 .plastic package (such as in the case of yard waste? or .
..cause the fragmentation and,disappearance.of .litter and so ;,3..:~ SUMMA Y.OF THE.INVENTION ~

~,J, ! j ~ia~t ~r317~ .. Theipres53ent~inventioni;isldirected to b~odegradable I .
;s~polymer.. composition ~which~obvijates one~or more of;.the ~ I
n~def~cts~of.conventiona.}.biodegr~3idableires n~ The ::
Ij composition~of.ijthis inyent;ion:.comprisesi~and intimate :.: .mixture.of .~ I s~ r ' I ~t~ d.5 a) ~one:or more~polymers::rand~ *~ * ,.

I

i ~'' ., ............. . . . -, . . . . . . .

W~ gl/06601 Z~ ~r ~9 PCTIUS90/06363 ;;`` ~3~
~ b) an effective amosunt nf one or more particulate fillers which comprise one or more degrada~ion enhancing materials which enhance the biodegradation of the polymers, which materials are associated with one or more biodegradable and degradable saEening materials which inhibit the activity of said degradation enhancing materials during said association whereby on ' biodegradation or degradation of said safening material -' the activity of said~enhancing materials is completely or partially restosred. ' - Another aspec5 of this invention relates to an article of manufacture fabricated totally or in part from the biodegradable composition of this invention.
Sevéral beneficial effects are provided by the invention. For example, low cioncentrations of the particulate filler are required in'order to ps~ovide an accep~able level of disintegration of the composition within'a reasonable period of time. The degradatiosn enhancisng'material is released when the composition is exposed to environmental (biodegradation) conditions, and 20--is not time dépendent'. Thus,':there is no danger or substantially reduced'danger of'premature degradation and associated shelf'l'ife problems. ~A~wide ~ariety`of degradation enhancing materials and safening materials having a wide ~ariety-of properties can'be used,'which facilitates'the use of the invention`with a wide variety ' ~ 'of"polymers''and'environmental conditions. Some usèful degradation'~enhasncing materials not only cause fàilure of 't'hérpolymer''due-to'ltheir own?'àctivity, bùS~ also'promote fùrthe'r'''bio~egradation of thé safen'ing material an'd/or other biodegradabl'e` additives tha`tlmay;ibe'in the'~
('' 'I''com'position'~'c'au'i'ng'a cascading 'effèce'.'"~

~ .!O.l i~l'l i :-ts;; ';~ RIEF~'DEscRIpT ~ ~'5''' -~-!~ 35 i-~'s~ Thi's''invent'Lo'n1'can''be~'be~er3~undërs~'oo'd':fr'om'w'a ' ' '?'consideration'~oe'ith`e ispe'c'ificat'ion'in'conjunction'with the ~ 'drawingi~ in which: ' `~ ' ' ~:
,` . , .
;` :

WO9~/06601 ~ PCT/~S90/06363 Figure l is a graph indicating the degree to which high density polyethylene is protected by beta-cyclodextrin.
Figure 2 is a graph indicating the conductance of the ~ormation and degradation of a beta-cyclodextrin sodium dodecyl sulfate complex.
Figure 3 is a graph indicating the conductance of the ~ormation of a beta-cyclodextrin cetyl pyrdinium chloride complex and of a starch/cetyl pyridinium chloride complex.
Figure 4 is a graph indicating the conductance of the formation and degradation of a corn starchisodium dodecyl sulfate complex.

, DESCRIPTION OF THE PREFERRED EM~ODIMENTS
The composition of this invention comprises two :~essential ingredient. One essential ingredient is a polymeric resin. ,The type of polymeric resin used may ~.' vary widely.. Illustrative of useful resins are aromatic, , aliphatic and cycloaliphatic polyamides such as 2~ poly(m-xylylene adipamide), poly~p-xylylene sebacamide), ~,., poly,2,2,2-trimethyl-hexamethylene terephthalamide), poly (piperazine sebacamide).,,.poly.~metaphenylene ~
-isophthalamide) ~Nomex), poly ! p-phenylene ..; ,,-terephthalamide),~,(Kevlar): the copo,lyamide of.~30 . ,hexamethylen.e.,diammon,ium .L~,ophthalate.and ?% -:.. hexamethylene,,diammonium,adipate, the~copolyamide .o~ up to 30~jbis-(,amidocyclo-hexyl)m~ethylene~terephthalic~acid n~ a.ndicaProlact~am~polyhexame~thylene adipami,de ~nylon 66), poly~butyrolactam) ~nylon 4), ~ poly~ ~9i-amLnonoanoic, acid) tnylon~9),,.poly~enantho,lactam);(nylon~-7), ~
; poly~caprylla,c,tam)`~nylon 8,), polycaprolactam~!nylon 6), poly ~p-phenylene terephthalamide), polyhexamethylene - sebacamide,(nylon 6jlO),~polyaminoundecanamide ~nylon ll), polydodecono-lactam (nylon 12), polyhexamethylene 35 ~is,pp,hthalam~ide,~cpolyhexamethylene,,lt~ereph~thalamide, ~-'' ' "
n~ .poIycaproamide,; poly~nonamethylene azelamide~j(,nylon 9,9), , ::
- - , . ., ... ~ . .

: ~ ., ~ . - : ''' W091/06601 ~ ~ 9 PCT/US90tO6363 poly(decamethylene aæelamide) (nylon 10,9), poly(decamethylene sebacami de ~ ( nylon 10,10), poly[bis-(4-aminocyclothexyl) methane 1,10- `-decanedicarboxamide] (Qiana) (trans), or combination thereof; and aliphatic, cycloaliphatic and aroma~ic polyesters such as poly(l,4-cyclohexlidene dimethyl eneterephathalate) cis and trans, poly~ethylene-l, 5-naphthalate), poly~ethylene-2,6-naphthalate), poly(l, 4-cyclohexane dimethylene terephthalate) (~rans), poly(decamethylene terephthalate), poly(ethylene terephthalate), polytethylene isophthalate), poly(ethylene oxybenozoate), poly(para-hydroxy benzoate), poly(dimethylpeopiolactone), poly(decamethylene adipate), poly(ethylene succinate), poly(ethylene aæelate), poly(decamethylene sebacate), poly(~ dimethyl- :.
'propiolactone), and the like.
Also illustrative of useful polymeric resins are polymers copolymers formed by polymerization of ,~
-unsaturated monomers of the formula: :
~ Rl R2-C = CH2 whereLn~
j ...Ri and R2 are the same'-or different'a'nd'are '' hydrogen,hydroxy,'ha'logen, ~alkylcarbonyl, carboxy, ~
alkoxycarbonyl, heterocycle or alkyl or ary"l ei'ther -.unsubstituted or:substituted with one or more substLtuents ;7i selected from the group;consisting of alkox'y, cyano,-hydroxyj.alkyl::and aryl,.-'lllustrative''of 'such`polymèrs of ~ L'B-unsaturated~monomers.-are'polymers including .
; ~po}ystyrene-, polyethylen'e,`plyprop'ylene'~:~poly't'l-o'ctadencë), .~. cpolyl~obutylene,~poly(l-pë'ntene), poly(2-méthylstyre'ne), polyt4-methylstyrene), poly(l-hexene), po'lytl-'pentene), .po~y(4-me~hoxystrene),epoly(5-methyl''l-hexene~
npoly~4-methylpen~ene)~-/Jpoly`~l''butenë), polyvinyl ;~ F
2chloridè,~polybu.tylene, polyàcrylonitrile,`~poly'(me't~'yl pentene~ poly(vinyl3alcohol)',~"poly(vinylacëtat'e')"'~
~ polyt'vlnyl`~utyral), poly~vinyl"chl'oridê), poly(vinylidene '' ~ ' : - - ':"
, : .
.
. ... , , ..... i . . .
- . ~ .

, . . :, . : .. , ,, . .. ~. :,, . : .

2 ~ 9 WOgl/066~1 PCT/US90/06363 ... . . f~

chloride), vinyl chloride-vinyl acetate chloride copolymer, poly(vinylidene fluoride), poly~methyl acrylate, poly(methyl methacrylate), poly~methacrylo-nitrile), poly(acrylamide), poly(vinyl fluoride), poly(vinyl formal), poly(3-methyl-l-butene), poly(l-pentene), poly(4-methyl-1-butene), poly(l-pentene), poly~4-methyl-1-pentence, poly(l-hexane), poly(5-methyl-1-hexene)~ poly(l-octadence), poly~vinyl-cyclopentane), poly(vinylcyclothexane), poly(a~vinyl-naphthalene), poly(vinyl methyl ether), polytvinyl-ethylether), poly(vinyl propylether~, poly(vinyl carbazole), poly(vinyl pyrolidone), poly(2-chlorostyrene), poly(4-chlorostyrene), poly(vinyl formate), poly(vinyl butyl ether), poly(vinyl octyl ether), poly(vinyl methyl ketone), poly(methylisopropenyl ketone), poly(4-phenylstyrene) and the }ike.
Preferred resins for use in the composition of this invention are resins which are commonly used in the fabrication of packaging materials such as polyethylene, polyethylene terephthalate, polystyrene, polyurethane, polyvinyl chloride, polypropylene, polycarbonate and blends of such materials. The above list of preferred is merely intended to be representative of useful and preferred resins,.and other resins which are.used as packaging materials.may!also be used. ~In the.most referred embodiments of this invention, the.resins of choice.are polyethylene (high density, low:density and llnear~low density), polyethylene terephthalate,:polyvinyl ehloride, polyurethane;~and.blends of-such:polymers.t.
The second essential ingredient.of the.composition of this,invent.ionji.s~.~an-effective amount:of a particulate ' fil?er.~;"The.filler is~a~material whichiis.designed~to be inactive during~th~e3use of the composition and~whLch~
enhances~the degradat.ion~off~thelpolymer on.!exposure~of the composition~of thi~-~,invention~to a suitable environment,as for~examp}e~a{ga~rbage~dump or landfLll.~The~filler.lis ~ :
comprised...oj~a,degradation-enhancing~material~which is.
,, ", . . . . .. . .
~ effectivejto enhance3the.jdegradation,of~.the;polymeric 1 . . . :
:
.
. , .

, ~ . ... : . . . .
. ~; , , . , : .

W091/06601 ' PCT/U~90/~6363 material and a biodegradable safening agent which inhibits the activity of the enhancing material. In operation, the safening material associates with the degradation enhancing agent, thereby completely or partially inhibiting its activity during the association. On exposure of the composition to a suitable environment containing agent(s) effective to biodegrade the biodegradable safening material, the activity of the enhancing material is competely or partially restored, which results in an enhancement of degradation of the 10 pOlymer-As used herein, ~association~ is any chemical,physical or like interaction between the biodegradable safeni~g material and the degradation enhancing material which completely or partially inhibits the biodegradation -enhancing characteristics of the degradation enhancing material, and which allows a complete or partial restoration of such characteristic's on the biodegradation of the biodegradable safening material. The nature of the association between the biodegradable safening material and the degradation enhancing materiàl may vary widely and 'essentially depends on the properties of these two ma'terials. The'only requirement is`that this'association '~'''inhibits the activity of the enhancing'material during the association', and that this activity'is totally or ~ ~' part'ially restored on biodegradation'of'the sa~ening material.': 'Cert`ain represe'ntative associat'ion's~'include : ionic and covalent bonding as for example in the case of th~e'ion'i~cibon'ding of a''~met''al~'with cellulose'asrin'sodium cellulose-,~the ioni`c'bonding'of-metal ~saLts' ànd io'n`ic 30`"~'speciè's`su'c'h'l~as''metallsalt's!of fatty'acids'~as or ëxample s'odlum s~earate and various'covàlent fatty 'àcid l '1 der'i'vativ~e~s suc`~'as''''f'att'y''acid dèr'iva't'ives'`of-~protè`ins or ~"; ^}/'cà'r~ohy'dra'te's'.'^~Other fo''èms-of'ass'oc'iàtionCinclùdè non ' co'v''à'le''t*l'a'ssodiationfs'~''sucEi3~'à's'inte'rc'al''àtion',i~'in'ci'ursion~lC~
35'~ i;complexation~,'ic'h'ëiat~loh~`an'd'non-specific~à'dsorption'as for' 'i examplë the'"'i'nclu~lon~!'of''a'hydro'phob'ic surfactant or ''`stress'cracking agen~iwithin the''cavity o;aicyclodextrin , .

.

WO91/06601 PCT/US90tO6363 -8- ~:
molecule. Still other forms of association includes incapsulation where the enhancing material is physically encapsulated and surrounded by the safening material.
Suitable safening agents may vary widely. Any material which is degradable and which is capable of inhibiting the biodegradation enhancing activity of the enhancing material can be used. As used herein, a material is "degradableR where it degrades as a eesult of exposure to the environmental effects of sunlight, heat, water, oxygen, pollutants, microorganisms, insects and/oc animals Usually such materials are naturally occurring and are usually "biodegradableq. As used herein, ~biodegradableU materials are those which are degraded by microorganisms or by enzymes and the like produced by such microorganisms. Illustrative of suitable safening materials are starches and starch derivatives such as rice and maize starch, dextrin, cyclodextrin, amylose, . amylopectin, defatted or solvent extracted starch, and the like. Other useful safening materials include sugars and derivatives thereof, such as sucrose, dexteose, maltose, mannose, galactose, lactose, fructose, glucose, glyamic acid, gluconic acid,.maltobionic acid, lactobionic acid, . lactosazone,.glucosazone, and the,like. Still other useul sa~ening materials.are cellulos~ and derivatives thereof such as esters...of cellulose as for example, .triacetate cellulose,..acetate cellulose, acetate- .
.. .. . .. . . .. . . . . . . .. .. . . . . . .
.. butyrate cellulose,~nitrate cellulose.and sul~ate ; .. ... cellulose, ethers of.cellulose.as for example,.ethyl ether . ~ceLlulose,~hydroxymethyl ether.cellulose!~hydroxypropyl . .. ether cellulose, carboxymethyl.ether.celLulose,.~, ; 30 ~-~ ^ .......................... . ...... . .
;,;.l.n~;ethylhydroxy ether..cellulose! and..cyanoethylether ether cellulo~e,~ether-esters o~`cellulose as for?cexample, apetoxyethyll~ether~cellulose~lproplonoxypropyl~celluloser .and? benzoyloxypropyljce}lulose.and~urethanel~cellulose as ,foriexample~J~phenyl.;urethane ce}lulose.~Other.~useful ..,~3,5 :`~ safening;.~agents include;peoteins;suchJas~,zein!~soy~.protein ..or proteLn,hydrolysat.es,icasein, collagen,~elastin,.
. ialbumins and the like and! llgnins. Useiul biodegradable .

. . - . ~. . . .:: . . . . . , -2 ~ $ ~.?~ 9 WO~1/06601 ~ .`.P~/US90/06363 safening materials also include fats and fatty acids such as mono-, di- and tri-glycerides derived from animal or plant material and the common derivatives of these fats such as fats obtained from peanut oil, corn oil, coconut oil, cottonseed oil, palm oil and tallow, and fatty acids such as oleic acid, stearic acid, lauric acid, myristic acid and palmitic acid; biodegradable anti-oxidants such as tocophenols, rosemary trosemari-quinone) and mustard seed extracts, ascorbic acid and compounds closely related to vitamin C such as ascorbic acid-2-phosphates and ascorbic acid-6-fatty acid esters propionic acid; and biodegradable polymers such as poly(glycolide), poly(tetramethylene carbonate), poly(lactide), poly(glycolide co-lactide), poly(caprolactone), poly(tartaric acid), poly(ethylene-co-ketone acetal), poly(hexamethylene azelate), poly(decamethylene ' succinate), poly(decamethylene azelate)! poly(ethylene succinate) 9 poly(hexamethy}ene sebacat@), poly(ethylene azelate), poly~r3-methoxy-4-hydroxy styrene), polytamino '' triazole), poly(hydroxy butyrate), poly(hydroxyvalerate), ~ 'poly(hydroxy butiyrate-co-hydroxy valerate), poly(dihydropyranj, poly(spiro ortho carbonate) and poly~l-phe'nylalan'ine/ethylene glycoljl,6-diisocyanato '~ ihexane);' ''~
' ' ;Preferred biodegradable safening materials are-starch -5 ~and-starch derivatives'such as~cyclodëxtrins,.fats, fatty , ., , .. . . , . ,.. - , . ~-, ;, . . . . .
~ - 'acids'~and biodegradable polymers such as poly(carbonates), J ` and'homopblymers and copolyrmers derived from the .................... ''' polymer-ization-of hydroxy alkanoic acids and their iderivat'ives'su'ch'as polylZ~l-hydroxy butyrate),

3 ZZ~ r~ r j, ~ ,~ "
poly~lactide), polyglycolic acid and copolymers thereof`~
: and particularly preferred biodegradable safening .. , mater1als'are starchès and starch derivatives and biodegradable polymers derived from the polymerization of hydroXyalkanoic acids and their derivatives ~. Most.i ~
9 Z;~ ,t ~ i r ,~ ~Z ~t C Z l ' ~ `5 ~
preferred b~odegradablé sa~ening agents~are cyclodextrin'sZ, ~A poly~beta-'hy'droxybutyrate), poly(lactides) poly(glycolide) and block copolymers containing WO91/06601 2 ~i~J..~19 PCT/US90/06363 ~
1 0 ~
3-hydroxybutyrate glycolide and/or lactide recurring monomeric units.
~ seful degradation enhancing materials include any material which in an unassociated form is capable of directly or indirectly enhancing the degradation of a polymeric material to some extent and which is capable o~
association with a biodegradable safening material which inhibits the activity of the enhancing material, such activity being restored on biodegradation o the biodegradable safening material. Useful enhancing materials may vary widely. Illustrative of useful materials are stress cracking agents as for example, surfactants. Useful surfactants include, anionic, cationic, zwitterionic and nonionic surfactants.
Useful anionic sur~actants include alkali metal, ammonium and amine soaps and alkali metal salts of alkyl-aryl sulfonic acids, sodium dialkyl sulfosuccinate, sulfated or sulfonated oils such as glycocholic acid sodium'salt~ glycodeoxycholic acid sodium salt, sodium dioxychalate, cholic acid sodium salt, l-deconesulfonic acid sodium salt, caprylic acid sodium salt, sodium dodecyl sulfate, taurocholic acid sodium salt, t'au'rodeoxycholic acid sodium salt, sodium decyl sulfate, sodium octyl sulfate, sodium hexyl carboxylate,.sodium ';-hep'tyl carboxylate,~'so'dium octyl carboxylate,.sodium nonyl 5- ^carboxylate, sodium decyl caeboxylate and sod~um dodècyl ~-'carboxylate, disodium 'dodc'yl phosphate, disodium 4-alkyl 3-sulfonatosuccinates and sodium dodecyl benzènesulfonate.
;Us'efu'l~c'ationic su'rfa"cta'nts i`nciude salts.oe long chain primary,'isecondar'y 'and tertiary amines such as ~:
.'~'o'le'ylaminë acetate, cetylam'ine acètatè, didodecyiamine lactate',7the acetate of'aminoethyl-amino ethyl.stearamide, .
dLlau'royl triethylene~'tetramine diacetate, and .-...-~i.
aminoet'hyi-2~hépt''adëcenyl'~niidazolLné' acetate' ~
quatërnary~s'alts''such as'cétylpyrïdinium bromidë,~ ~ ;'c 35! L^1hex'odecyl ethyi morpholinium ch1Orlde, didodecyl ammonium chloride, cetyipyridinium chloride, dodecyltrimethyl- :
- ammonium bromide, he'xadecyl trime~hylammonium bromide, ' '' .

., ..... . .. , , .. . . . .. . .. : ..

W~91/0660] ''.".; PCT/US90/06363 ~`., - - 1 1 -tetradecyl trimethylammonium bromide, dodecyl ammonium chloride, cetyl trimethyl ammonium bromide, benzalkonium chloride, decomethonium bromide, methylben~ethonium chloride, 4-picoline dodecyl sulfate, sodium perfluorooctanoate, sodium hexyl sulfosuccinate, sodium octyl sulfosuccinate, sodium cyclohexyl acetate, sodium cyclohexyl propionate, sodium cyclohexyl butanoate and sodium cyclohexyl sulfamate.
Useful zwitterionic surfactants include N-alkyl-N,N-dimethyl-3-ammonio-1-propane sulfonates such as N-decyl-N,N-dimethyl-3-ammonio-1-propane~ N-dodecyl~N,N-dimethyl-3-ammonio-l propane, N-hexadecyl-N,N-dimethyl-3-ammonio-1-propane, N-octyl-N,N-dimethyl-3-ammonio-1-propane, and N-dodecyl-N,N-dimethyl 3-ammonio-1-propane, D,L-alpha-phosphatidyl choline and dipalmatioyl.
Useful nonionic surfactants include n-alkyl-D- '.
glucopyranosides and n-alkyl-D-maltosides such as decyl-D-glueopyranoside, dodecyl-D-glucopyranoside, heptyl-D-glucopyranoside, octyl-D-glucopyranoside, 20 nonyl-D-glucopyranoside, decyl-D-maltoside, dodecyl-D- . .
; maltoside, heptyl-D-maltoside, octyl-D-maltoside, and nonyl-D-maltoside, condensation products of higher Eatty : alcohols with alkylene,oxides, suchtas-the'reaction product o~ oley} alcohol with 10 ethylene oxide unit's;
condenstation products of.alkylphenols with alkylene ~ oxides, suchjas the reaction products of isooctylphenol, : j o~c.~tylphenol and nonylphenol.with from abut 12-to aboùt 30 .~ ,e~hylene.oxide,units; çondensation.pro'ducts of higher`' ~fa$ty acjid.a~ides;i~with.5.or.;more alky'lene oxide units such - ~ as ethylene oxLde units;:~polye~hyl glycol esters of long chain fatty~acids,lsuch as.~tetraethyleAe glycol monopalmitate, hexaethyleneglycol monolaurate,`'i''' ';`
~nonaethyleneglycol dioleate,~tridecaéthyle'neglycol mojnoa.rachidata,-triosaethylene"glycol~-mono~ehënate,;~''i . .
5 ~1tjricosae~5h,yleneglycoldLbehanat!e,ipolyh'ydric~àicohoï;' par~ial~hi~her~fatty.~àcid-.est.eri~"suc'h'5as~'sorbitan'i' `'9 trisearat~e,;ethylene~ox.ide~condensat'ion prodù'cti~3Of~
polyhydric .alcohol.parital hi~her ~atty.esters, and their 1:
' :

. .
.
~', .

WO91/06601 ~ PCT/US90/06363 -l2~
inner anhydrides (mannitol-anhydride, called Mannitan, and sorbi~ol-anhydride, called Soebitan), such as glycerol monopalmitate reacted with l0 molecules ofethylene oxide, pentaerythritol monooleate reacted with 12 molecules of ethylene oxide, sorbitan monostearate reacted with io to 15 molecules of ethylene oxide: long chain polyglycols in which one hydroxyl group is esterified with a higher fatty acid and the other hdroxy group is etherified with a low:
molecular alcohol, such as methoxypolyethylene glycol S50 monostearate (550 meaning the average molecular weight of the polyglycol ether).
A combination o~ two or more of these surfactants may be used. For example, a cationic surfactant may be blended with a nonionic surfactant, or an anionic surfactant with a nonionic surfactant.
Other useful degradation enhancing material include olefins especially mono, di and tri unsaturated fatty acids, triglycerides and derivatives such as lipoproteins and lipopolysacharides agents capable of a change in physical properties..upon exposuee to environmental conditions such as moisture,.for example, bentonite `clay;
oxidizing agents such as.halogens and heterosubstitut'ed anions,.especially~tri iodide-(I3); strong acidsj strong bases and certain salts such as'trifluoroacitic'acid, dichloroacetic acid,:hydrochloric''acid," lithium bromide,.
25 r Z~Lnc clorid,e, sodium cyanide,'phospho'ric acid, 'nitric .~. aci~d, sulfuric.acid,-~sodium'.hydroxide, lithium hydroxide, . apd.sodium~alkoxide;.and transition ~,etal salts'(cobalt, copp;er,~nickel,~zinc, manganese,~ cadmiùm,ii'iron) alone oc in combinat~ion,.with organic compounds!such as fatty acids ~e.g, steara~e or naphthenate, and the~i'ike)jasisàlt ''complexes..J;~-$~,ji..i,:;i'; ~""' "'i''' ''~`''' ~Still~,c,ther useeul;degradation enhancina, ~,ateriàis , '~
:include~sc-lvepts and,other-materials'~which'ë'nh'àn'ce the' degr~adation...,of ,jspecif ic ,po lymers ;~as':!fo~ ;éxampl!e ~, ' hèxarle/~
35 heptane~ ,$icQbutyl.~acetate,- 5-me't'~yl"'2'-'hiexatnc,ne,'J~ :
2-pentanone,,J,,3,-pentanone,^.ctoluenè,Scycl'o`hexanë,jJànd~,' .t.etrahydro~uran which~are~'detrimèntal~to~p'o'ly~bu'tadienes);

~' .

W~91/0660~ PCT1US90/06363 t : -13-xylene, p-xylene, tetralin, decalin, tetrachlocoethylene, n-butyl acetate, diphenyl ether, butyl sterate, squalene, glycol dipalmitate, tripalmitin which are detrimental to polyethylene, pol~(propylene) and poly(tetrafluoro-ethylene~; N,N-dimethylformamide, N,N-dimethylacetamide, Y-bUtyrolactone, nitric acid, hydroxyacetonitrile, dimethylformamide, ethylene carbonate, propylene carbonate, malonitrile, su~cinonitrile, sulfuric acid, which are detrimental to polyacrylonitrile; cyclohexanone, cyclopentanone, and tetrahydrofuran which are detrimental l~ to poly(vinyl chloride); acetonitrile, heptanone-4, isoamyl acetate, n-butyl chloride, heptanone-3, .
n-propanol, acetone, benzene, n-butyl acetate, n-butyl chloride, and chloroform which are detrimental to poly(methylmethacrylate) benzene, toluene, butanone, and cyclohexanone which are detrimental to poly(styrene);
phenol, o-chlorophenol, aniline, cyclopentanone, ethylene carbonate~.cyclohexanone, benzyl alcohol, acetic anhydride, and dimethyl formamide which are detrimental to . poly~oxymethylene?; o-chlorophenol, phenol, 2~ trifluoroacetic acid, and dichloeoacetic acid which are detrimental to poly(ethylene terephthalate, nylon 6 and nylon 66;and.mineral acids such as HCl,..HBrj-H2SO4j..
and H3PO4, trifluoroacetic acid, inorganic salts such as Ca(SCN~2,jLiSCN,iNaSCN, LiI, NaIj KI, and K2~gI4l), strong bases such as LLOH, and~NaO~
tetraalkyl-bases,~metal complex solutions..such as (lcu!~NH3~4](~oH)2/~dimethyl~sul~oxlde~J-and .i ^ :.
dimethylfocma~ide which,are1detrimental.-;to:.cellulosic .~,m~aterials. r,~;i J i~
."3J~ .Preferred;.degradation ~nhancing materials are stre~ss cracking.~agents~which are.materials which cause the;1 .. ...
..,.. r,.polymer~com~osition-to~crack,i,and;:particularly.pceferred ` ... ,i~degradation~.. enhancing materials:are surfactants... More ~preferred~surfactant~s.1are~capable;of!inot only-degrading 35~ theplasSic.~but~a1jso~exbibit~a benefici:al;effect..byit;
enhancing~he biodegrada~ion of any::biodegradable~ e.~
.. component i~corporated into-the plastic... Most.preferred .

.:
.
, .

WOsl/06~0~ 2~ 9 -14- PCT/USsO/06363 for use in the practice of this invention as degr~dat ion enhancing materials are nonionic surfactants, or mixtures of nonio~ic surfactants and other types of suefactants.
Particularly preferred for use in the practice of this invention are nonionic surfactants such surfactants are capable of not only degrading the polymees but also exhibit a beneficial effect by enhancing the biodegradation of any biodegradable component in the polymer. Preferred nonionic surfactants for use in the practice of this invention are alkylarylpolyethers, such as the condensation products o~ alkylphenols, such as octylphenol, nonylphenol and isooctyphenol, and alkylene oxides, such as ethylene oxide fatty acid alkanol amides;
poly-alkoxylated alcohols, such as polyethoxylated tridecanol, idotridecyl alcohol adduct with ethylene oxide and fatty alcohol polyethers.
The particularly biodegradation safening materials and degradation enhancing:material selected in any-particular situation will depend on a number of factors including the capability of the biodegradation safening 20 . material for inhibiting the activity of the degradation enhancing material, the level and nature of the activity of the.;degradation enhancing material, t~e poly~0ric : material.stability.of the complex,-especially as i~' pertains-to processing'condi~ions for:the polymeric' .
mateial and the effect.that the degradation enhancing material.has upon the biodegradation of-incor.porated components of.theipolymer, the propoied use'of~thë'' ' ' '~ composition~and::article:ifabricate'd therefrom,'thè~'cost of ~he composition and aeticle fabricated ~herefrom, the ~.............. .
.30 .;;?usable~lifetime of~theicomposition'and~àrticle'fabricated .therefrom, the tLme'after:'exposure t!o'biodegradat'ion environental):'conditions which degra`dati'on''is"~desired to 3-itake~place,~s'~For. example,~'when' the'degradation~'enhancing ,?~:imaterial~is a-isurfactantj~the~biodegràdation-safening-; .
; 35 material::~is.. preferably-a~'carbohydrat'e-s'u'ch as!st~arch or a : starch.derivative.~includLng 'amylos~j' lineae-?~
polysaccharides and cyclic~polysaccarides''such'as'' ' ~' -.~: . .. . . ,.. .... ..... .. , .. - . .,, . , . , .. . - , , - . . . . . .. . . . .

.' ' ' ~ . ' . , ' . ', . . .

WO91~6601 ~$~ 9 ` ~ ~ ~ PCT/US9~/06363 cyclodexteins which function to form an inclusion co~plex and encapsulate the surfactant and protect the polymeric material from the deteriorating effects of the surfactal~-. Biodegradation of the carbohydrate releases the surfactnat which can enhance the degradation of the polymeric material.
Similarly when the biodegradation enhancing material is potassium triiodide, the biodegradable safening . material is preferably a polysaccharide such as a starch which is capable of complexing the salt which functions to pre~ent or retard the formation of the halogen, I2 which adversely affects the polymeric material. Here again, on biodegradation of the starch, the I2 is released to enhance the degradation of the polymeric material.
The co~position of the invention includes an 'Aeffective amount~ of the particulate filler. As used herein, an ~effective amount~ is an amount which when activated is sufficient to enhance the biodegradation of the polymeric-material to any extent. This amount may ...~. vary widely and depends on a number of factors such as the 20 .amount and activity of the degradation enhancing material :. in the fiLler and the-like. In~general, the amount of ' ,' E,iller,employ,ed~is-at.,~least, about,-,O,.~OO,l,i,we.ight,percent -~.,based on the total weight.,,of the composition.-.-In the preferred embodiments of,.the,.invention, .the amount of the ,, 5 ,~filler is from~.about~Ø05 to.about 40 weight percent based .~,on the total weight of the composition,.~,and in ~he , ~, particularly-~-preferred embodiments of.the invention.is i...Er.om~about o.ol~to~about~i2oi~AweightFpercent on the : aforementioned.basis.!!,Amongst.these.,particularly rpr.efer.red -embodiments; most~preferred.-are ,those ,~
embodiments~.in.,.which~the amount~of the~filler, is"rom abou,t; l to~abo.ut,ilO~weightrpercent~bas~d..o,n-lthe..total n~.weight of,the-~c,o,,mposition~ v,~t .,~ t~Ci.' ..~ .tt~
~dL; ~he filler,ctis-yi~particulate form to~.al.lowi;dispersion ; of the ~iller in the polymeric material.1c,~In~thej~preferred '~ t~C~ t~:embodiments;.~-Pf :thel~inv,en~ion,~the~part.iclezsize is equal ~ to ori~less than.about;lOOO.~um.. ;~he lowee limit,in~

:

WO91/0660l ~ a~ ~ 9 PCTtUS90/06363 particle size is not critical, and in the preferred embodiments of the invention, the size of the particles is as small as possible which facilitates the dispersion of the ~iller in the polymeric ~aterial. In the more preEerred embodiments of the invention, the particle size is from about 0.1 to about 500 ~m, and in the most pceferred embodiments of the invention, particle size is from about l to about 300 ~m. Amongst the most preferred embodiments of the invention, tho~e in which the particle size is from about 2 to about 200 ~m are the embodiments of choice.
In addition to the above-described essential components, the composition of this invention can include various optional components which are additives commonly employed with polymers. Optional components include fillers, nucleating agents, plasticizers, impact modifiers, chain extenders, pigments, colorants, mold release agents, antioxidants, ultra violet light stabilizees, lubricants, antistatic agents, fire retardants, and the like. These optional components are well known to those of skill in the art, and accordingly, will not be described herein in detail.
!'` ;~i ~':,Th'e''compos'ition'may fu'rther-comprise additional' 'particulate biodegradable~fillers which ~urther enhance "-' t'he'~r'ate of biodegradation of the composition.
5 -'Illustrative:of'useful and pr'efer'red~fille'rs 'are those materials described as useful for-biodegradable safening ';mater'ials. Preferred fillers are~starches. ' r~ The amount of b'iodegr'a'dable~fille'r m'ay vary widely and'~:amounts ~normally used lin the art~maylbe used. -Howeverj- in the~prefe`rred 'embodimets of~the invention, the 'amo'unt o~'such biodegradable filler is~not more;than about !3o~wleight~percent~ basedton-the~total weight:of the~5 composition and more preferably not-more~than about~20 we~fghtt~percent~an~ most'~pre'ferably~not-more tha~n about l0 ~35`'J'weight~'percent'.;~ le ''~~
i The~-composition~'bf,this inven~ion~can berprepa~ed by blending or mixing the essential ingredients,~ and other .

~ g W~ 91/~6601 ' ' .~ PCT/VS90/06363 optional components, as uniformly as possible employing any conventional blending means. Appropriate blending means, such as melt extrusion, batch melting and the like, are well known in the art and will not be described herein in greater detail. In one useful procedure, the blent~ing procedure can be carried out at elevated temperatures above the melting point of the polymer and the nucleating.
agent either preformed, or as individual components of the agent separately oe as a combination of the components in a suitable form as for example, granules, pellets and preEerably powders is added to the melt with vigorous stirring. Alternatively, all or a portion of ~he various .
components of the filler can-be masterbatched.or preblended with the polymer in the melt and this premixed ...
or masterbatch added.to.the polymer in the melt in amounts .'.
- ~suEficient to provide the desired amount''of the filler in the polymer product. "'Stirring is continued until a .homogeneous composition is1for~ed. 'Blending temperatures ~ :' and blending pressures, and the order of addition of the vaeious components are not critical and may be varied as 20 ~ desired provided that a substantially homogeneous :
. composition results. The blending procedure can be .' car.ried:out.at~ elevated~temperatures,:in:whi'chLcàse the '' .polymer component is melted:and the-~filler and~othér optional ingredients a're admixed therewith by vigorou~ly . .:.
.ii..stir.ring the melt.~Similarly, th'e`"'various solL'd ' ;
components -can be -granulatéd;iland the granulat'-'d'' ~
. c.omponents~mixed dcy~in;a suitable-blender,`' or''for ~ :
example,l(.alBanbury.mixer~, ~''s uni'forml'y''a`s`"pos'sibie, then : m~lted'in an~extruder~randr'extruded w'ithlc'o'oli'ng.~
ni~.The~.composit'ions ac'cor'ding'toi:t'he~.inv'ent'i'orn''~are'~ ;' .thermoplastic.~biodegradable~im'at~èrial's''from~which'molded .
articles.^of manù'factu're~can~be produce'd~''by te:conventional JO.,shapin~g',.pro~esses~~ suchl~a's~.'me~ spi'nn'lng',~'casting, ~
l`nject.ion~molding ~and~-`extru'd'ing'.'~ Thè compositi'ons~ of' ;
' 35 thls inven'tion!~are'~'especi,~ y'~useful'for"'fa~r"ic'at~io~n of '~ ;extruded films,?ae~;for'~'ex'amplië~ f~ m~s `for use~rin''food packaging ?rSuch fi-lms.can be .fabr'icated using conventional ' , wosl/0660l 2~ ~ ~ 18- pcT/vsso/o6363 film extrusion techniques. Such films foemed from the composition o~ this invention are biodegradable such as being buried or composted with other garbage, the film degraded by evironmental effects such as sunlight, heat, water, oxygen, pollutants, microorganisms, and the like.
The following examples are presented to more fully illustrate the invention and are not to be construed as limitations thereon.

EXAMPLE I

A) Preparation of the ~-Cyclodextrin tCD) Com~lex The molecular complex of CD with Igepal was prepared by combining the individual soluble components and recovrerng the precipitated complex. In 100 ml of 15 water 15 grams of-CD was dissolved by heating. A 5 ml ,, solution of 32~ Igepal ~Igepal C0630), a non-ionic surfactant obtained from GAF Corporation was warmed to reduce its viscosity and then added dropwise into the hot CD solution over a period of about 15 minutes wi~h constant stirring. The solution was next alowed to cool slowly to room temperature and then maintained at 4 C foe approximately,l15 houes.; The resul~ant pre,cipitated~;
complex~was recovered by filteation and then air dried.
, .. . . . .
~. ,,To ei~timate the ratio of CD to Igepal in the complex a known,weigh~ of complex was,subjected to extensive acid hydeolysis so as to fully degrade the cyclodextrin to its ' , component glucose units,,which could then be measueed Using a,glucoi3,e analyzer (Beckman Instrumen~s). The amount of cyclodextrin!in ,thej,complex,,can;thus be `;,;
determined,~7 glucoise molecules per l ~-cyclodextrin . ". ~ ... . ... ~ . .
molecule) with th,e,,~remainder,~o the;,weight ofithei~complex due,~,~t~,o,;,the Igepal~ ,In,on,e,example,~lSO mg of the,complex was hy~d~rolyze~d~by;~re~qf~luxLng~for~l.5 hours ,at~i:100 C!in?~100 ml,o~~rl M~Cl~ The-gl,ucose"-pr,oduced ~was,measured and accounted,,~for,~115.,3~mg of ~the;<samplelwtih -38 mg .~
re~presenting the cont,ribution of~,the Igepali Using the ,mo,lecu,lar,weights, of .the cyclodextri'n and~Igepal-the'ratio '..

,g~/06601 ~ Y PCI/U~;90/06363 of cyclodextrin to Igepal in the complex was determined to be approx ~ately 1.6 to 1.

B) Testing of the Complex. To test the ability of the complex to function as a biologically released destructive agent a method was developed to measure the destructive effect of the release of the stress cracking agent, Igepal. The assay method developed for this purpose uses small pieces of polyethylene which are st~essed by gentle bending in the middle of a 1 cm by 3 cm sample. The ends of the pieces are held together to maintain the gentle stress and thus provide a point o~
failure for the plastic and reduce the time for the assay and the samples are immersed in the test solution. Normal crazing and stress c~acking will occur withou~ the introducton of an external stress, bu~ in a longer time fram. This assay method was first used to determine the , appropriate concentration of Igepal to be used for for stress cracking. The results are set ~orth in Figure 1.
As shown in Figure l, a concentration of greater than 0.05 ,"20,,, ,mM was found to-completely, or nearly comple~ely, break ; the plastic samples in the stress cracking assay within 24 hours at 60C. The p`rotective effect of the cyclodextrin encapsulant was demonstrated in a similar~experiment in which cyclodextrin was added to the'aforementioned testing ' mixture (0.05 mM Igepal). The Igepal,,no,,longer,,,broke thè
plastic samples and stress cracking was either ,low or not measurable. To demonstra~e the biodegradability of such a i~ r ~
complex and ~he results of the rèlease of the Igepal, the same test ~as:run, except that the enzyme alpha' amyl'ase ' ,30 ,,.which,.is,.known.to~degrade cyclodextrins was added to'the ~ tm~ x~t~ure.~ he~result-3Llo~flthLstè~xperiment is also depicted "I 3,in,F,lgure,l ~andj~shows~hat,a;~normal mi~crobial,enzyme,,is capablerof relea~ing ~he-,a~detrimental~agent-~(Igepal) from ~thejc,omp,l,~x ,l~wlth~CD)f~and,~hat,3lthe~fr~ee~agentj,can ",elst,~r~Y,i,ltj,h,,e Plag,~lC~ oJ,~ ? J . '1 :''.i 'l'i'~ '!.'` ~,` !

. . ' ~

,, -. ` , :,, ~ ' . : . :
- , ~ : ' . . , . . : , , . : .:

- ' - . : ' . , : '.

W~9l/06601 PCT/US90/06363 C) ~ ~ ~ =~ ' polyethylene (HDPE). ~Cyclodextrin and the complex o CD
with Igepal were incorporated into HDPE to produce a plastic product of ten mil thickness containing the approptiate additives at a level o~ lO~i by weight. The physical properties of the final products (and a control plastic containing no additive) are shown in the following Table 1.

leA~
Sample Wt~ @ yield @ break -ID filler psi psi (1) Control 0 40~0 1741 . (2j I~epal Complex in beta-Cyclodextrin - 10 :~. 3803 1636 (3) beta-C~lodextrin-3703 3309 .
..
TABLE 1 ~cont'd) .. . Elonyation . - Tensile .~ .
Q yield @ break . .Impact .~
ft-lb/in .3 ~493.0 ~ 84.6`
`(2)'4 ~ 52-9 ,, 37.9 , .~~.(3)~ .8. ~18.g .~ 1.2 To'determine'if thé ^complex'in the plàstic was sùsceptible sto~iodegradation, the1samplës were placed in a;n enzyme soiution'containLnc'~àlpha`j'àmylase and glucoamylasë which . :
~make~possible ~t~e~.degra~dàtionJof the cyclodëxtrLn 'and its;F. ~ ;
conversion to glucose. Glucose is readiiy measùrëd using an instrument isuch as a glucose analyzer lBechman .

':~ ' . . ~, ,. , . . ' , ~ , . .. . .

' ' ' . '. . ' ' ' ' ' .' . '' . '.' ". " . ' '.~ ' ' . " ' ' . '.. .' ' ' .

W091/06601 ~ "1,~L~'9 PCT/US90/06363 -2l-Instruments). ~he results of this experiment are shown in the following Table 2.

' TABLE 2 ~ degradation of cyclodextrin control:
Time (h) HDPE + complex HDPE ~ cyclodextrin no en2yme only O O` O O ..
10 2.8 .40 ~ .92 l9 .73 .94 0 201 Z.3 0 .
The production of glucose during the time period of the test shows that the cyclodéxtrin within the plastic can be degraded by microbial enzymes, As shown in the tests described above, the deg~radation of the cyclodextrin ~.. .. . . . . .
portion of the cyclodextrin/Igepal complex will liberate the Igepàl. The Igepal will in!turn cause stress cracking of the plastic, With the samples chosen for the testing o~ the incorporation of the complex into the plastic ~10%
i loading) it was not possible"to show the result of stress cracking in our standard test~within a short period of 25 time. In part, this is due to t~e difference in the low ~ "
~''''tëmpèra~ùres uséd to a-ccelërat'e 'a'nd''t~est'~'the'''st'ress J: cracking, Furthermore, in order to demonstrate 1 - ' ~ '~ `' cycLodextrin degradation (glucose production) the 10%, :, ~f i ',S`',~j'J ~(~tf~f'i! '~2r; ~ i ;,a~f5~ t.' .~
loading was appropriate, however, this relatively high 1~ ' '? l C'S~ r~ 'f~ f~ .3 i?~
~' 30 level Oe complex addition caused a siufficient change in ~;
the'physical properties so as to affect the response of "
the plastLc to stress cracking,failure.
~ f i~ J '~ ?f~ f ~ Uir~ 'r,f~ t~i'~ ?~ Ir.~ '.~
~ ~ "r,`f i ?,5~ t~ ' r"~
' ' '' ' ~' WO9~/0660l Z ~ PCT/US90/06363,,~

EXAMPLE II

Complexation and Degradation of a ~-Cyclodextrin With Sodium Dodecyl Sulfate (SDS) and of ~-Cyclodextrin and Corn Starch Wlth Cetyl PYridinium Chloride (CPC). Using the procedure of Example I, the complexation of cyclodextrin with destructive agents other than Igepal was demonstrated using positively and negatively charged surfactants. In both cases the formation and degradation of the complex were monitored by changes in the conductance of the solution. As the low molecular weight, charged surfactant was immobilized by the formation of a complex with cyclodextrini and conductivity decreased.
Upon addition of an appropriate enzyme to degrade the cyclodextrin, the conductivity again rose indicating the release of the destructive agent in solution. An example of this effect is shown in Figures 2 and 3 in which the formation and degradation ~by the addition of the enzyme alpha-amylase) of a beta-cyclodextrin complex with SDS and and the formation of a beta-cyclodextrin complex and a corn starch complex with CPS are measured by conductivity changes.
.. ,...,.. .: , , EXAMPLE I I I
.. . :. . . .... . . . .
, ! ' ~ Using ' the procedure of Example'I, the compléxa~ion and , degradation of corn''starch 5Pearl Starchj was demonstrated with sodium dodecyl suIfate. As shown"by monitoring conductivity'changés ~Figure 4) starch can complex a ''strëi's,~-cracking'surfàctan~'~SDS), and release it upon enzymat ic degradat ion. Since starch has been widely used ,, as an addit ive to piastics, it foLlows that thè
starch/surfactant complex could b~ added then the suractant released upon exposure to conditions which 35 pcomote biodegradation. c~'.

~, ,' ' , . . , . ~ . , , ~ . .: , ; . . ~ , ; .
,- .'. ... - ,' ` . ,:, .: '. .. '' '

Claims (10)

WHAT IS CLAIMED IS:

1. A biodegradable composition comprising a mixture of:
a) one or more polymers; and b) an effective amount of one or more particulate fillers which comprise one or more degradation enhancing materials which enhances the biodegradation of said polymers associated with one or more biodegradable safening materials which inhibit the activity of said degradation enhancing materials during said association, and on biodegradation of said safening materials the activity of said enhancing materials is restored.

2. A composition according to claim 1 wherein said polymers are selected from the group consisting of polyethylene, polyethylene terephthalate, polystyrene, polyurethane, polyvinyl chloride.
polypropylene and polycarbonate.

3. A composition according to claim 1 wherein said biodegradable safening materials are selected from the group consisting of starch and starch derivatives, fats, fatty acids, biodegradable polymers and combinations thereof.

4. A composition according to claim 3 wherein said biodegradable safening materials are selected from the group consisting of starches and starch derivatives, polymers derived from the polymerization of hydroxy alkanoic acids and mixtures thereof.

5. A composition according to claim 4 wherein said safening materials are selected from the group consisting of cyclodextrins, poly(beta-hydroxy butyrate), poly(hydroxy valerate), poly(lactides), poly(glycolide), block copolymers containing beta-hydroxy butyrate, glycolide and/or lactide recurring monomeric units and mixtures thereof.

6. A composition according to claim 1 wherein said degradation enhancing materials are selected from the group consisting of stress cracking agents.

7. A composition according to claim 6 wherein said degradation enhancing materials are selected from the group consisting of surfactants.

8. A composition according to claim 7 wherein at least one or said surfactants is a non-ionic surfactant.

9. A composition according to claim 1 wherein the amount of the particulate filler is at least about 0.001 weight percent based on the total weight of the composition.

10. A composition according to claim 1 wherein the particle size of the filler is equal to or less than about 100 µm.