CRYSTAL-STRUCTURE OF STEREOCOMPLEX OF POLY(L-LACTIDE) AND POLY(D-LACTIDE)
CRYSTAL-STRUCTURE OF STEREOCOMPLEX OF POLY(L-LACTIDE) AND POLY(D-LACTIDE)
复制标题
DOI：
10.1080/00222349108245788
复制
发表时间：
1991-01-01
期刊：
影响因子：
--
通讯作者：
IKADA, Y
中科院分区：
文献类型：
--
作者：
OKIHARA, T;TSUJI, M;IKADA, Y
将聚（L-丙交酯）和聚（D-丙交酯）的等摩尔混合物结晶成立体络合物，其晶系为三斜晶系（P1），晶胞尺寸为：a = 0.196 nm，b = 0.916 nm，c（链轴）= 0.870 nm，α = 109.2 度，β = 109.2 度，gamma = 109.8 度。 在晶胞中，聚(L-丙交酯)链段和聚(D-丙交酯)链段成对包含并以平行方式横向堆积。 复合物中的L-和D-聚丙交酯呈3(1)螺旋构象，该构象是从具有α-形式的均聚物晶体中的10(3)螺旋稍微延伸出来的。 均聚物也能够采用 3(1) 螺旋构象并形成 β 型晶体。 均聚物晶体中的3(1)螺旋不如10(3)螺旋稳定，因此β型很容易通过退火转变为α型。
An equimolar mixture of poly(L-lactide) and poly(D-lactide) was crystallized into a stereocomplex whose crystal system is triclinic (P1) with cell dimensions: a = 0.196 nm, b = 0.916 nm, c (chain axis) = 0.870 nm, alpha = 109.2-degrees, beta = 109.2-degrees, and gamma = 109.8-degrees. In the unit cell, a poly(L-lactide) segment and a poly (D-lactide) segment are contained as a pair and packed laterally in parallel fashion. The L- and D-poly(lactides) in the complex take a 3(1) helical conformation, which is a little extended from a 10(3) helix in the homopolymer crystal with the alpha-form. Homopolymers are also able to take the 3(1) helical conformation and form the beta-form crystal. The 3(1) helix in the homopolymer crystal is less stable than the 10(3) one, and hence the beta-form is easily transformed to the alpha-form by annealing.