Abstract It has been believed that stereo-irregular polymers hardly form crystalline structure because of the deficient ordering along the backbone direction. Here we show the crystallization of atactic polymers by rapid thermal quenching of polymers co-melted with a chain-stretching agent. To this end, crystalline PMMAs (hc-PMMAs) are prepared from stereo-irregular atactic-PMMAs (Mn = 35–1500 kg/mol) as well as stereo-regular isotactic- and syndiotactic-PMMAs by rapid quenching of molten PMMA/benzoic acid (BA) solutions. BA acts as a chain-stretching agent. PMMA chains are elongated up to 60% of their contour length when they are co-melted with BA. The preferential hydrogen bonding between PMMA and BA compensates the conformational entropy loss of PMMA chains in molten PMMA/BA solutions. Upon quenching, PMMA chains are further stretched because of the large tensile stress induced by the sudden temperature drop and because of mechanical squeezing by concomitant directional crystallization of anisotropic lath-like BA crystals. After sublimation of BA, the PMMA shows a clear melting transition: Tm = 276–283 °C for hc-s-PMMA and 293–306 °C for hc-a-PMMA. Unlike other conventional crystals having 3D crystallinity, hc-PMMAs exhibits 1D crystallinity due to ordered lateral packing between chains (d = ∼4.3 A) which is independent on the tacticity while the packing is amorphous-like for the other two directions. For the reason of the reduced dimensionality in crystallinity, we named the crystalline PMMA as 1D hypo-crystalline PMMA (hc-PMMA). Because of their high 1D crystallinity (55–65%), hc-PMMAs exhibit the storage modulus (E′) enhanced by 20 times comparing with those of pristine PMMA.

中文翻译：

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一维亚晶：立体不规则聚合物结晶的新概念

摘要 人们认为，由于沿主链方向的有序性不足，立体不规则聚合物很难形成晶体结构。在这里，我们通过与链拉伸剂共熔的聚合物的快速热淬灭来展示无规聚合物的结晶。为此，结晶 PMMAs (hc-PMMAs) 由立体不规则的无规 PMMAs (Mn = 35–1500 kg/mol) 以及立体规则的全同立构和间同立构 PMMAs 快速淬火熔融 PMMA/苯甲酸酸 (BA) 溶液。BA 充当链拉伸剂。当 PMMA 链与 BA 共熔时，它们会被拉长至其轮廓长度的 60%。PMMA 和 BA 之间的优先氢键补偿了 PMMA/BA 溶液中 PMMA 链的构象熵损失。淬火后，由于突然的温度下降引起的大拉伸应力以及由于各向异性板条状 BA 晶体伴随定向结晶引起的机械挤压，PMMA 链进一步拉伸。BA 升华后，PMMA 显示出明显的熔化转变：hc-s-PMMA 的 Tm = 276–283 °C，hc-a-PMMA 的 Tm = 293–306 °C。与具有 3D 结晶度的其他常规晶体不同，hc-PMMA 表现出 1D 结晶度，这是由于链之间的有序横向堆积 (d = ∼4.3 A) 与立构规整度无关，而其他两个方向的堆积是无定形的。由于结晶度的维数降低，我们将结晶 PMMA 命名为一维亚晶 PMMA（hc-PMMA）。由于它们的高一维结晶度（55-65%），