Nhựa phân hủy sinh học trong đời sống: Quá khứ, hiện tại và tương lai

Hgi nghi Khoa hoc ky- niim 35 ndm Viin KH&CNVN - Hd Not -10/2010<br /> <br /> <br /> NHlTA PHAN HUY SINH HOC TRONG DC>I SONG:<br /> QUA KHir, HIEN TAI VA Tl/ONG LAI<br /> Ho Son Lam<br /> Vien Khoa hoc vat lieu ung dung<br /> S6 I.Mac DTnh Chi, Quan l-Thanh pho Ho Chi Minh<br /> Email: sonlamho05@,vahoo.com<br /> Tom tat:<br /> Bdi viit gidi thiiu sa luge sit rg ddi cita nhiing nghiin citu vi polymer lit phdn<br /> hiiy sinh hoc vd tinh cdp thiit cUng nhu y nghia vi ly ludn thuc tiin cita nd. Cdc<br /> du bdg vi mdi Irudng ciia trdi ddt tron§ vdi thdp Min tdi chu trgng vdn di rdc<br /> Ihdi vd mdt^ trong nhiing nguy ca tiim dn Id cdc vdt lieu polymer khdng lit phdn<br /> hiiy. Mdt sd ung dung cua palymer tu phdn hiiy sinh hgc trong 30 ndm qua dugc<br /> di cap den. Bdi viit cUng dd gidi thiiu edc dgng polymer tu phdn hiiy sinh hoe<br /> Irong tu nhiin ciing nhu qua con dudng tdng hgp. Qua dd gidi thiiu tinh hinh<br /> nghiin citu dgng vdt lieu ndy a trong nude vd trin thi gidi, ddng thdi cd gdng ggi<br /> md mdt sd hudng di cho cdc nghiin ciru vi polymer tu phdn hiiy sinh hoc tgi Viet<br /> ngm trgng ihdi gian tdi trin ca sd cdc hgp chdt hihi ca tu nhiin.<br /> Abstract:<br /> The present article are inlraduce the study of conspectus of biodegradable<br /> Polymers. During fifty year, since first biodeagradable polymer are synthesized,<br /> biodegradable polymer have more and more role in the life, to give an overview<br /> of the necessity and application of biodegradable polymer, the present posture of<br /> research and applieation of biodegradable in the world and in Vietnam.<br /> Furthermore, Ihe present article are introduce a few form, structure and category<br /> of biodegradable polymer, and proclaim the trend of research those in Vietnam<br /> Key words: Polymer, biodegradable polymer.<br /> <br /> <br /> 1. Mo-dau:<br /> Trong the ky thu 19, nhung phat minh ciia H.Braconnot (1811), Charies<br /> Goodyear(1839), F.Walton(1844), A.Parkes(1862), hay Bing phat minh Zelluloid dugc dang<br /> ky dau tien tai USA nam 1870 da md ra nhimg trang sir mdi cho su phat triln nganh nhua,<br /> chat deo, polymer cung nhu thilt bi cho san xuit chiing. Nhung ciing tir dd, trong nhimg nani<br /> 60-70 ciia the ky 20, ngudi ta nhan ra ring, mdi trudng dang bi buy hoai bdi nhimg boat ddng<br /> tao ra cac san pham mdi ciia chinh minh. Mat trai cua nhirng phat minh tren da hien rd va<br /> ngudi ta phai bat dau nghi din nhimg vat lieu polymer khac "than thien" vdi mdi trudng ban.<br /> Trong nhimg phat minh mdi nhit ciia xu hudng dd, nam 1960 Davis va Geek [1,2,3] da tdng<br /> hop thanh cdng mdt trong nhirng polymer tu phan buy sinh hoc dau tien tren co sd<br /> Polyglicolide. Va sau dd la cac poly(D,L, DL lactide).Chi khau tu tieu mang nhan hieu<br /> DEXON ra ddi da md ra mpt hudng di mdi trong tdng hgp polymer, va tir dd, ngudi ta chu y<br /> den polymer phan hiiy sinh hpc nhilu hon, hy vpng nd se la cuu canh cho mdi trudng.<br /> 2. Cac dang polymer tu phan huy sinh hoc: Polymer tir phan buy sinh hoc tdn tai trong 3<br /> dang chinh:<br /> <br /> 2.1.Polyester duac san sinh b&i cdc vi sinh vgt: Cac loai polymer nay d dang nguyen<br /> thuy nhu poly(hydroxyalkanoate) nhan dugc bdi cac chiing vi sinh vat chuyin hda cac san<br /> pham thien nhien nhu tinh bdt, chat beo va tu phan buy hoan toan trong dit, nude sdng, sudi<br /> hay trong bien. Co nhieu dang khac nhau cua poly(hydroxyalkanaate) dugc con ngudi tao ra<br /> <br /> 191<br /> Tiiu ban Khoa hoc vdt lieu ISBN: 978-604-913-011-3<br /> <br /> <br /> bang sir chpn lua chinh xac cau tnic ciia ngudn cac bon thien nhien. Mac dii vay. cac loai<br /> polymer nay khdng the san xuat dai tra tren qui md cdng nghiep \ i chi phi eao, nen ngudi ta<br /> chii trpng sir dung cac hgp chat do thien nhien tao ra nhu la nguyen lieu cho tdng hgp polymer<br /> tu phan buy sinh hpc.<br /> 2.2. Polysacharide thien nhien vd cdc polymer thien nhien: Polysaccharide dugc<br /> diing nhieu trong y te dudi cac dang cellulose, cellulose va cac ddng ding ciia nd, heparin,<br /> dextrin, pullulan, pectin, chitin, chitosan hayluronic acid va alginate. Mpt sd img dung quan<br /> trpng ciia cac hgp chat cellulose: Cac hgp chat cellulose nhu metyl-, ethyl-, aminoethyl-, hay<br /> acetate-phthalate- dugc sir dung lam mang Ipc trong may chay than nhan tao[4], lam vd bpc<br /> thude vien, bang vet thuang[5], chat lam tang sir tuong thich trong mau[4], va thudng dugc sir<br /> dung trong viec Ipc mau vdi vai trd eiia chat chdng ddng tu, hay dugc diing lam chat truyen<br /> dan plasma trong dung dich . Chitin va chitosan ciing la mpt dang polysaccharide, dupe phat<br /> hien tir nam 1811 do H.Braconnot trong khi nghien cuu ve nam va dat ten la fungine. Ngay<br /> nay chitin va chitosan dugc nghien cim va img dung rdng rai, dac biet trong ITnh vuc dugc va<br /> y te[6]. Hau bet cac dang polysaccharide tu nhien khac nhu heparin, alginat... deu dugc sir<br /> dung cho muc dich y te va dugc pham.<br /> 2.3. Polymer PHSH tong hffp, dgc biet Id cdc polyester beo: Cac polyester beo nhu<br /> poly(e-caprolacton), poly(D,L, DL-lactide), poly(butylene sucsinate)...da trd thanh thuong<br /> pham va dau ra ciia chiing ngay cang tang len. Ben canh cac loai polymer TPHSH nay, cac<br /> nha khoa hpc da va dang sang tao va thir nghiem nhieu loai khac cho ung dung thuc te nhu<br /> poly (ester amide), poly(carbonat), poIy( ester urethane).<br /> 3. Tinh hinh nghien ciin trong va ngoai nude;<br /> 3.1. Tmh hinh nghien ciiu & nu&c ngodi: Ci cac nude cd nin khoa hpc tien tiln, viec<br /> nghien cim polymer t\r phan hiiy sinh hpc dugc tien hanh tir lau [7], tren nhilu hudng, dac<br /> biet trong ITnh vuc y te. Trong nhung nam gan day, da cd hang tram cdng trinh dang tren cac<br /> tap chi chuyen nganh polymer ve cac polymer tu phan hiiy sinh hpc, dac biet la ddng thdng tin<br /> dugc tap hgp trong "Polymeric Biomaterials" do Severian Dumitriu , University of<br /> Sherbrooke Quebec Canada[8] suu tap va xuat ban qua cdng ty Marcel Dekker Inc, vdi tdng<br /> lugng 44 cdng trinh trong 1168 trang. Mai tdi nam 1986 Hang ICI mdi dilu cbl dugc Biopol,<br /> mpt loai nhua nhiet ed ngudn gdc tir thuc vat, cd the tu buy dugc trong thien nhien. Mdt vai<br /> nam sau dd mpt loai nhua cd dac tinh tuong tu, MaterB, dugc dilu cbl bdi hang<br /> Montedison.Han gudc ciing cho ra ddi Enpol.[9].Hien nay cac san phim ciia Biopol va<br /> MasterB dang chiem ITnh thi trudng chat deo phan hiiy sinh hpc ciia thi gidi.<br /> 3.2. Tinh hinh nghien cuu & trong nu&c: 6 Viet nam, cac nha khoa hpc trong cac<br /> vien nghien cim hoac cac trudng dai hpc, trong mudi nam trd lai day da cd nhiing nghien cim<br /> theo hudng ndi tren, dac biet cac nghien cim ve chitin va chitosan da thu dugc nhung kit qua<br /> tdt. [10 ] LTnh vyc nghien eiiru bien tinh polymer truyen thdng bing mdt so acetat kim loai<br /> ciing da dugc tien hanh[l 1,12]. Hien dang cd de tai cap Nha nude ve biln tinh tinh bpt vdi<br /> polymer truyen thdng de tao nen polymer cd the phan huy. Trong tuyen tap cac cdng trinh va<br /> bao cao khoa hpc ciia Phan vien khoa hpc Vat lieu tai TPHCM [13] da cd dl cap din polymer<br /> tu phan huy tren ca sd acid lactic chuyen hoa thanh lactide va polylactide. Kit qua cho thiy<br /> mau polymer cd kha nang phan hiiy hoan toan khi chdn trong dat sau thdi gian 30 ngay. Gin<br /> day, nhdm tac gia tren cQng da cdng bd mdt so ket qua khao sat qua trinh tdng hgp<br /> polyanhydric sucinic tren mpt sd xiic tac khac nhau[14] hay tdng hgp mang polymer<br /> composite tren ca sd polyvinylancohol va sgi lignocellulosic[15]. Mpt cong trinh khac cua<br /> Trudng DHKHTN [16] da gidi thieu phan ung triing hgp sdng polymer metyl metacrylat bing<br /> he xiic tac oxy boa khir.<br /> <br /> <br /> 192<br />  Hoi nghi Khoa hoc ky' niim 35 ndm Viin KH&CNVN - Hd Ngi -10/2010<br /> <br /> <br /> 4. Tuong lai cua polymer phan buy sinh hoc: Do olygomer va polymer truyin thdng di tir<br /> nguyen lieu hda thach cd cac mach chinh chi chira lien ket cacbon - cacbon (loai trir loai cd<br /> nhdm cue tinh cdng kenh d mach chinh nhu PVA) cho thay it cd phan irng xuc tac phan hu\'<br /> bang enzym, dac biet khi KEPT ciia chiing Idn.Vi v$y thdi gian phan buy cua chiing trong<br /> dieu kien tu nhien hay chdn ii keo dai. De giiip thiic day qua trinh nay, ngudi ta da nghien cuu<br /> bien tinh chiing. Mdt sd phuang phap sau:<br /> 4.1. Dua nhdm cd lien kit yeu vao mgch polymer: Cd nhilu each dl dua "lien kit<br /> yeu" vao mach chinh ciia nhimg polymer nay. Nhirng "lien ket ylu" dugc thilt kl cho phep<br /> kiem soat su phan hiiy cua polymer ky nude KEPT Idn thanh polymer KEPT thip ban. dl<br /> sau dd vi sinh tieu boa thdng qua qua trinh phan hiiy sinh hpc.<br /> 4.1.1. Biin tinh Polypropylen (PP) v&i tinh bpt: San phim lai diu tien tren thi trudng<br /> loai nay la Biopropylen CP Bio-PP-50 - mpt hon hgp ciia polypropylen homopolymer trdn<br /> vdi 50% tinh bpt va mpt hon hgp ciia chat deo hda hoac phu gia. Biopropylen cd dp cung. bin<br /> va chiu nhiet cao ban so vdi PP nhung lai cd dp gian va bin ca hpc kem ban. Khdng gidng<br /> nhu cac polymer sinh hpc khac, Biopropylen khdng can phai siy khd.<br /> 4.1.2. Biin tinh PVC: Ddi vdi PVC, la mpt polymer truyin thdng khdng PHSH ngay,<br /> cd the bien tinh nd de tao ra nhung he polymer mdi ma van dam bao tinh chit ciia \'at lieu<br /> nhung de phan hiiy de chuyen sang giai dpan phan hiiy sinh hpc vdi thdi gian nhanh ban khi<br /> chua bien tinh.<br /> 4.1.3. Ket hop phuc kim Ipai v&i VC: Mdt sd y tudng mdi trong viec sir dung cac<br /> phuc he ciia kim Ipai chuyen tiep de kit hgp vdi VC: Trong phan iing nay, monomer VC dugc<br /> gan vdi phirc he va hinh thanh moi lien he Zr-Cl va propylene. Kit qua la atactic<br /> poly(propylene) vdi khoi lupng phan tir thip (khdang 500) dugc hinh thanh.<br /> 4.1.4. Bien tinh PE bdng CaC03: Hien tai, cac nha gia cdng chit deo da san xuit<br /> thanh cdng cac loai tiii dung chit lupng cao chira tdi 15 - 20% CaC03. Mpt sd loai mang<br /> mdng hoac vat lieu deo trong mpt vai ung dung khac cd thi chiia len tdi 30% chit ddn nay. 6<br /> chau Au, cac mang mdng diing dl bpc ba cd thi chira tdi 60% CaC03.<br /> 4.1.5. Bien tinh polystyrene: Hien nay, polystyren (PS) dugc sir dung rpng rai lam<br /> bao bi thuc pham do cd chi phi thip va tinh each dien. Tuy nhien, do ap lyc vl giam tac dpng<br /> ciia rac thai bao bi dang budc cac nha may cbl biln thuc phim phai tim cac vat lieu thay thi<br /> than mdi trudng hon. Cac hop PS thudng cd thi mit hang tram nam de phan buy, kl ca da<br /> dugc tang tdc nhd hda chat phu gia va cac phuang phap khac. Tuy nhien. cac hda chit va<br /> phuang phap nay deu rat dit va cung gay hai cho mdi trudng.<br /> 4.1.6. Bien tinh polyuretan thdnh : Bpt xdp pol>airetan mim dugc<br /> diing de nhdi cac ghe sofa va dem, cdn bpt polyuretan cimg dugc sir dung dl san xuit cac tim<br /> ngan trong cac cdng trinh xay dung. Hai loai bpt nay chiim phin^ Idn thi trudng bpt<br /> polyuretan. Cdn cd 2 loai bpt polyuretan khac cd cac img dung dac biet dd la bpt \'i xdp^dugc<br /> sir dung de che tao vo lang d td hoac Idt ben trong mu phdng hp thi thao va bpt dan hdi dugc<br /> su dung de che tao de cua cac loai giay, kl ca giay thi thao. Tuy ca 4 loai bpt polyuretan nay<br /> cd cac tinh chat vat ly khac nhau nhung diu dugc tao ra bing each thuc hien cac phan ung<br /> triing hgp gdm diol (hoac rugu da chirc). diisoxyanat va nude.<br /> 4.2. Tao vat lieu composite giira polymer truyen thong va polymer PHSH: Viec<br /> su dung PVA vdi mpt sd chat khac nhu tinh bpt, x e n l u l o z c . d l tao nen nhihia dang vat lieu<br /> he polymer composite cd chat lugng tdt cung la hudng nghien cim biln tinh polvmer tnivin<br /> thong CO trien xpng cao. Neu xet tren khia canh do bin vat lieu thi su kit hgp giira polymer<br /> <br /> <br /> 193<br /> Tieu ban Khoa hgc vdt lieu ISBN: 978-604-913-011-3<br /> <br /> <br /> PHSH vdi mdt sd sgi gia cudng , nhu sgi thiiy tinh chang ban. se cho ta mdt vat lieu nidi cd<br /> dp ben cao han.Vi du sau day chung minh dieu dd:<br /> <br /> <br /> <br /> <br /> Hinh I; a-Dd bin udn. u-ung sudt ddn hdi<br /> Doi vdi cac polymer rieng re nhu tinh bdt hay polylactide, dp ben udn va ung suat dan<br /> hoi thudng khdng bang nhau va ed dp chenh lech tir vai phan tram den gan 50%. Nhung khi<br /> cd sir kit hop vdi sgi thiiy tinh gia cudng de tao thanh dang polymer mdi GFRP (Glass-Fibre-<br /> Reinforced-Polymer) thi dp ben udn va img suat dan hdi ciia cac palymer PHSH ndi tren dat<br /> cue dai (100%).<br /> 4.3. VinapoP- tai sao khong? N I U tren the gidi da cd Biopol, Master B, Bioxo hay<br /> Enpol, lieu Viet nam cd the cd Vinapol®? Cac nghien cim gan day ciia Vien khoa hpc vat lieu<br /> img dung thupc Vien KH&CN Viet nam cho thay da hinh thanh mpt chudi cdng nghe de tdng<br /> hgp mdt dang polymer phan buy sinh hpc tren ca sd ciia cac san pham ndng nghiep nhu dau<br /> beo, xenlulozo, tinh bpt va glyxerin - san pham phu tir qua trinh san xuat biodiesel.Mac dii<br /> tinh chat vat ly cua Vinapol chua cd dp ben keo nhu cac polymer truyen thdng, nhung nd lai<br /> cd eae kha nang khac nhu hiit am ( 600 lan so vdi trpng lupng ciia nd), phan buy hoan toan<br /> thanh CO2 va H2O trong vdng 30-45 ngay khi chdn trong dat. Khi sir dung lam bau uam cay,<br /> nd khdng chi cd tac dung giir am ma cdn lam cho dat tai, xdp, tang kha nang phat trien ciia<br /> cay trdng. VINAPOL® la mdt polymer nen, dang vien cau hay khdi try (theo y mudn cua nha<br /> san xuat). Khi sir dung, chi can hda tan trong nude am (70-80 °C) de tao thanh dang theo<br /> khudn. Tiiy vao muc dich sir dung ma cd nhirng dang vinapol® khac nhau: Vinapol®-FAW:<br /> (Film Adsorption Water),diing lam bau uam cay, Vinapol*-FfT: ( Film for Fruit) diing lam<br /> mang bpc hoa qua. Vinapol*-PL/AW(Plastic Adsorption Water), diing de bpc Phan cac loai (<br /> Vd CO, hiin ca. visinh...).<br /> Bang cam quan ve mau sac ciia vd ngoai, ca chua bpc bang mang phan buy sinh hpc giir<br /> dupe kha lau so vdi bpc bang giay bao , de ngoai khdng khi, va bpc bang mang nylon thi<br /> trudng. Mau dd ciia qua ca chua sau mpt tuan van tuoi nguyen so vdi cac qua ca chua ddi<br /> chung va cac qua ca chua bpc bang cac vat lieu khac.<br /> Qua ca chua bpc bang mang nylon thi trudng cho mau sac chuyen sang sam ban, sau 15<br /> ngay vd ca chua khd dan dan den nut ra va hu. Trong khi dd, ca bpc bang mang phan<br /> buy sinh hpc khdng cd hien tupng nirt va hu sau 15 ngay.<br /> Chiing tdi dang tiep tuc khao sat chat lugng ( ham lugng vitamin, nude, khoang chit) ciia<br /> Ca chua cd va khdng cd vd bpc bang mang Vinapol*-FfF<br /> 5. Ket luan<br /> Polymer tu phan hiiy sinh hpc la mpt dang trong he vat lieu td hgp va cao phan tir,<br /> chua cd nhieu nghien ciiru d Viet nam, cdn d tren the gidi, dac biet d cac nude cd nin khoa<br /> hpc tien tien, ngudi ta da dau tu cho nhirng nghien cuu nay kha lau va tuy da thu dugc nhimg<br /> thanh tich -vugt trdi, nhung van chua the dem ap dung dai tra vi gia thanh ciia nd.<br /> <br /> <br /> 194<br />