Muaj peb txoj hauv kev loj rau kev npaj PLA polylactic acid

1. Direct polycondensation method (ib kauj ruam txoj kev)

Direct condensation ntawm lactic acid monomers kuj hu ua ib-kauj ruam polymerization. Nyob rau hauv lub xub ntiag ntawm ib tug dehydrating neeg sawv cev, cov hydroxyl thiab carboxyl pawg nyob rau hauv lub lactic acid molecule yog dehydrated los ntawm tshav kub thiab ncaj qha condensed rau hauv oligomers. Ib qho catalyst ntxiv, qhov kub thiab txias tseem nce ntxiv, thiab qhov hnyav ntawm cov txheeb ze molecular ntawm polylactic acid polymerizes rau hauv cov txheeb ze dua molecular hnyav polylactic acid.

2. Ob-kauj ruam txoj kev

Lactic acid yog siv los tsim cyclic dimeric lactide, uas yog qhib thiab polycondensed rau hauv polylactic acid. Cov thev naus laus zis no kuj paub tab, thiab cov txheej txheem tseem ceeb yog cov khoom siv raw yog fermented los ntawm cov kab mob kom tau lactic acid, thiab tom qab ntawd tom qab ua kom zoo, lub cev qhuav dej oligomerization, kub-kub tawg, thiab thaum kawg polymerization rau hauv polylactic acid.

3. Cov tshuaj tiv thaiv extrusion los npaj siab molecular hnyav polylactic acid

Polylactic acid nrog ib qho hnyav molecular ntawm 150, 000 tuaj yeem tau txais los ntawm kev sim ua kom yaj polymerization txuas ntxiv los ntawm kev sib txuas cov khoom sib xyaw ua ke thiab ntxaib ntsia hlau extruder. Ib tug ntxaib-ntsia hlau extruder yog siv los ntxiv polycondense qhov qis molar loj ntawm lactic acid prepolymer ntawm lub extruder los npaj cov molar loj ntawm polylactic acid.