sd vữa polymer trong sữa chữa +++

s dng va POLIMER TRONG sa cha CU C pgs .pts.nguyn v!"t t#ung$%! h&c g!a' th(ng v)n t*! +. ,a t#-t sa cha g.c /! 01ng 2 p'3y04# 5!"n t6nh+.+.7h-! 0!80 9Loai va sua cha ny cng c the goi l loai be tong xi mangpoocland-polymer hoac be tong Latex bien tnh hoac mot so ten goi khc , thuc chat l hon hop cua xi mang vi cot lieu doc tronvi nc m trong nc d c ho tan cc loai polymer hu co no d c tnh nang ph hop . Cc polymer d c cc phan tu ln doc ghp lai t hng nghn phan tu don gian . Cc polymer c dang Latex hoac dang bot khong tan . Latex l hon hop cua polymer hu co tan vi nc . khi dng loai bot khong tan th n s doc tron vi xi mang v cot lieu de sau d mi cng ha vo n-c . Ni chung ,cc chatLatex v bot khong tan doc che tao theo mot qu trnh giong nh khi polymer ha nh tong . Neu chi c mot loai monomer doc dng th polymer s l polymer dong nhat . Neu c hai hay nhieu monomer doc dng th polymer s l copolymer +.: . p'3y04# 3;0 $ Khi pha them polymer o nong do toi u th t nhat cng lm tang gap doi ga thnh cua nguyen lieu . nhng dieu ny tao ra chat long vat lieu sa cha tot hon so vi loai va thong thng . Thi gi tron can phai ngan nhng du hieu qua detrnh bot kh xam nhapvo va . Ngoi rav ty lenc / xi mangthng thap nen c yeu cau phai bao ve chong mat nc ngay sau khi thi cong de trnh cc vet nt co ngt-deo Nguyen nhan kinh te co ban khien chng tadng cc polymer trong hon hop xi mangl chng cai thien do dnh bm hoac tang doc do chong tham . Moi loai polymer dang dng hien nay deu cai thien doc do dnh bm nhng khong phai loai no cng tang doc do chong tham .Su lm bien tnh polymer cng s cai thien doc cc tnh chat khc nh cng do chiu uon , cng do chiu ko , cng do chong mi mn .v.v... Nhng thuc ra chng ta deu biet c nhng bien php re tien hon de dat doc cc muc tieu d .Macd su bien tnh polymer lm tang nhieu dac tnh tot ve cng do , n lai khong lm tang doc cng do nn , m doi khi cn lm giam cht t . Tuy nhien do cc loai va xi mang - polymer bien tnh khong di hoi viec bao dng am thong thng nen lai c the dat cng do nn cao hon so vi cc loai va tong tu cha doc lm bien tnh m lai khong doc bao dng am dng quy cch .So vi loai va tong tu khong bien tnh , su bien tnh polymer lm tang do t bien lm giam modul dn hoi v giam co ngt .+.? . c-c p'3y04# h'%t $@ng nh th" n;' .Su bien tnh polymer trong va xi mang doc khong che boi hai qu trnh - qu trnh thuy ha xi mang - qu trnh tao mng cua cc phan tu polymer Ni chung su thuy ha xi mang xay ra trc tien , sau d hon hop va s ha cng dan , cc phan tu(hat ) polymer tro nen bi tap trung trong ci khoang trong rong. v long nc giam dan di do chng tham gia vo qu trnh thuy ha xi mang , va c su tao hoi kh nen cc hat polymer dan dan bien doi thnh cc mng polymer . Cc mng ny lan vi xi mang d thuy ha cng bao phu cc hat cot lieu., nh the m cai thien doc nhieu tnh chat be tong so vi trng hop va xi mang tong tu m khong c polymer bien tnh .Chnh do yeu cau phai c doc hien tong tao mng polymer m va xi mang polymer bien tnh ( VXMPLMBT) c the cho php bao dng kho . Neu dng bien php bao dng t th su tao mng polymer s xay ra cham v s khong nhan doc het cc u diem cua polymer bien tnh . Do VXMPLMBT nhay cam hon vi cc vet nt co ngt -deo so vi be tong thong thng nen do am tong doi tren be mat cua n can phai doc duy tr c 100% cho den khi m cng do be tong dat du mc chiu dung doc luc do co ngt .Cc vet nt co ngt -deo xuat hien l do su bay hoi nc tren be mat hon hop .Do d phai bao d-ng bang cch ngan chan su boc hoi ny nh cc mng phu bao dng .+.A .3'%!p'3y04#n;' nBn dCng Cc loai polymer doc che tao bang cch nh tong ha polymer d doc dng rong ri trong nhieu ngnh nhng lai hau het khong thch hop de dng chung vi xi mang . Cc loaiLatexc the doc phan loai boi dau dien tch cua cc hat cua n. Neuhat c dau am ,chng l loai Anionic , neu hat c dau dong ,chng l Nonionic . Hon90% cc loai polymer doc che tao bang cch nh tong polymer hadeu l loai Anionic . Chng thieu su on dinh can thiet de chiu doc cc chat ho hoc thot ra t xi mang thuy ho . V vay moi loai polymer doc dng vi xi mang deu lloaiNoionnic v c hm long tong doi cao cua srfaetant hoac x phng .Sau day l danh sch cc polymer chnh doc dng vi xi mang :-copolymer Styrene-butadiene ( S-B ) -cc polymerv copolymer (Acrylic )Polyacrylic ester - copolymer Styrene-acrylic( S-A ) - homopolymer Vinyl acetate( PVA ) - copolymer Viniyl acetate ( VAC ) vi Ethylene,Acrylic ester hoac Vinyl ester cua axt versatic ( VEOVA ).Gi thnh cua polymer phu thuoc chu yeu vo cc monomer nguyen lieu .PVA l loairenhat , roi den VAC , roi S_B, roi S_A , v dat nhat l Acrylic . Nhng hien nhien l khong phai lc no cng chon dng PVA .Chat ny c 1 khuyet diem co ban : neu PVA tron vo VXMPLMBT m bi t th PVA mat cc tinh chat ho hoc tot v vat lieu tong hoo s c chat longkm hon va thong thng .Vay th nen dngVAC chang ? , Cng khong nen dng pho bien m chi dng cho trng hop be tong bi lo ra o noi am t nhng khong o trong nhng dieu kie khac nghiet .Loai va c S-Bcho cc tnh nang tot nhat , tr tnh on dinh mau sac di nh nang . Va cS-A khong c khuyet diem d , cnAcrylicth tot nhat 1. D . nBndCng 5@t haydCng dung dEch3at4/ Ni chung nen dng botpolymer neu dieu kien cho php hop l trong che tao va tron san . Nh vay s trnh doc viec phai cha vat lieu trong cc thng phuy . Che tao bot va trong Nh my cng s cho chat long tot hon .Vay tai sao khong chi su dung loai bot polymer . l v n dat hon . Muon c bot phai che tao xong dung dichLatex roi mi co dac lai thnhbot . Voy l dat gap1,5 - 2lan so vi Latex ban dauMot dac diem dng lu l vi hm long nh nhau th va c bot chi dat90 %cc tri so dac trng chat long so vi va c Latex .+.F .tG38phat#@n h