丙烯酰胺-苯乙烯双亲嵌段共聚物水溶液的表面活性及增溶性

在微乳液介质中制备了系列的丙烯酰胺 (AM)与苯乙烯 (St)的双亲嵌段共聚物 (PAM b PSt) ,用紫外分光光度法测定了共聚物的组成 ,用乌氏粘度计测定了共聚物的特性粘数 η],并用其相对表征共聚物的分子量大小 .重点研究了双亲嵌段共聚物 (PAM b PSt)疏水链段在水溶液中的缔合行为、共聚物的表面活性及其对有机物的增溶性能 ,考察了共聚物分子组成 (疏水链段含量 )与分子量对其表面活性与增溶性能的影响规律 .研究结果表明 ,由于疏水链段的憎水性 ,PAM b PSt的分子链在水溶液表面会形成表面吸附 ,从而降低水溶液的表面张力 ;而在水溶液中 ,在疏水相互作用下 ,PAM b PSt分子链中的苯乙烯疏水链段会形成分子间或分子内的胶束 ,烃类有机物可增溶其中 ;疏水链段含量越大 ,分子量越小 ,PAM b PSt的表面活性与增溶性能越强

STUDY ON SURFACE ACTIVITY AND SOLUBILIZATION OF AMPHIPHILIC BLOCK POLYMER OF ACRYLAMID-STYRENE IN AQUEOUS SOLUTION

Amphiphilic block copolymers have many unique physical and chemical properties,especially the strong self-assembling ability,because of the amphiphilic properties and microphase separation of their molecules.In this investigation,the amphiphilic block copolymers of acrylamide(AM) and styrene(St) were prepared in microemulsion medium.Two series of copolymers PAM-b-PSt were synthesized,one of them had variable composition,but an approximately constant molecular weight,and the other one had different molecular weight with an approximately constant composition.The composition of the copolymers was determined by ultraviolet spectrophotometry method,and the intrinsic viscosity of the copolymers from which the molecular weight of copolymers can be estimated relatively was determined by using an Ubbelohde viscometer.The association behavior of molecular chains of the amphiphilic block copolymer PAM-b-PSt in aqueous solution,its surface activity and solubilization ability were emphatically studied,and the effect of molecular composition and molecular weight on these properties was also investigated.The experimental result shows that the amphiphilic block copolymers PAM-b-PSt synthesized in microemulsion medium display some behavior of polymer surfacants.For example,because of the hydrophobic property of PSt blocks the molecular chains of PAM-b-PSt can form surface absorption on the surface layer of solutions resulting in an decreased surface tension of aqueous solutions,under hydrophobic interreaction the styrene blocks of PAM-b-PSt can form intermolecular and intramolecular micells in solution and the critical micell concentration of PAM-b-PSt is small.These micells can solubilize alkane substances,namely,the aqueous solution of PAM-b-PSt possesses solubilization ability for alkane substances.The higher the content of hydrophobic block sections is,the better the surface activity and solubilization ability of the copolymers are,and the smaller the molecular weight is,the better the surface activity and solubilization ability of the copolymers are.Obviously,because of the hydrophobic properties of PSt blocks the amphiphilic block copolymers synthesized in microemulsion medium have potential application prospects in enhanced oil recovery.