IPN's can be formed by preparing a crosslinked 联) polymer network,swelling(溶涨)in a second monomer together with activator(话性剂) and crosslinking agent(交联剂)，and polymerizing in situ(or in a definable condition).This second reaction forms a crosslinked polymeric network that interpenetrates the first network.A SIN differ from an IPN in that both networks are formed more or less simultaneously.IPN's and SIN's also form distinct and characteristic domain- type structures,with the restriction that both components must be continuous throughout the macroscopic mass. IEN's are prepared by mixing and coagulating ( two different kinds of polymeric latexes(胶乳)， followed by a single crosslinking reaction.The result is a three-dimensional mosaic(镶嵌)structure
IPN’s can be formed by preparing a crosslinked（交 联） polymer network, swelling（溶涨） in a second monomer together with activator （ 活 性 剂 ） and crosslinking agent（交联剂）, and polymerizing in situ( or in a definable condition). This second reaction forms a crosslinked polymeric network that interpenetrates the first network. A SIN differ from an IPN in that both networks are formed more or less simultaneously. IPN’s and SIN’s also form distinct and characteristic domaintype structures, with the restriction that both components must be continuous throughout the macroscopic mass. IEN’s are prepared by mixing and coagulating （凝固） two different kinds of polymeric latexes （ 胶 乳 ） , followed by a single crosslinking reaction. The result is a three-dimensional mosaic （镶嵌）structure
a.The microstructure(微观结构)and dimension of domain(相区)in blends: Physical blending dimension of domain um Chemical blending dimension of domain- -nm
a. The microstructure（微观结构） and dimension of domain（相区） in blends: Physical blending dimension of domain - μm Chemical blending dimension of domain- -nm
5.Compatibility(相容性)and composition of blends A.Compatibility
5. Compatibility（相容性） and composition of blends ⚫ A.Compatibility
Polymer blends are mixtures of different polymers without chemical bonding.The important criteria for compatibility or incompatibility (one or two phases)is the thermodynamics of the molecular state of dispersion and the adhesion between the two phases.Miscibility(混溶性)and compatibility are often used synonymously.Complete compatibility implies a polymer solution,which does not occur for blends of most high polymer because of unfavorable(不合适)free energies of interaction or mixing
Polymer blends are mixtures of different polymers without chemical bonding. The important criteria for compatibility or incompatibility (one or two phases) is the thermodynamics of the molecular state of dispersion and the adhesion between the two phases. Miscibility（混溶性） and compatibility are often used synonymously. Complete compatibility implies a polymer solution , which does not occur for blends of most high polymer because of unfavorable（不合适） free energies of interaction or mixing
Compatibility requires that the free energy of mixing be negative (which can only be achieved by exothermic(放热) mixing or a large entropy (of mixing. For most polymers,however,the mixing is endothermic(吸热)and the entropy contribution is small because of the high molecular weights.Therefore,most polymer blends are not compatible
Compatibility requires that the free energy of mixing be negative（－）, which can only be achieved by exothermic（放热） mixing or a large entropy（熵） of mixing. For most polymers, however, the mixing is endothermic（吸热） and the entropy contribution is small because of the high molecular weights. Therefore, most polymer blends are not compatible