The linear viscoelasticity and molecular structure of a series of poly(4-vinylbiphenyl) (PVBP) samples with polydispersities ranging from 1.08 to 2.75 are investigated using wide-angle X-ray scattering (WAXS), small-angle neutron scattering (SANS), and rheological measurements. PVBP chain dimensions, such as statistical segment length, persistence length, and packing length, are obtained from SANS measurements. Because of the bulkiness of the biphenyl monomer, PVBP has the lowest chain flexibility and the largest reptation tube diameter among most common thermoplastics, including polystyrene and polyvinylcyclohexane. Nevertheless, PVBP follows the universal power law dependence between elastic modulus and packing length (G_N⁰ ∝ p^–3). X-ray diffraction of PVBP consist of two main amorphous peaks: one associated with the interchain (backbone) correlations and a second one arising from phenyl–phenyl correlations. The latter are due to π–π stacking of the phenyl rings, mostly arranged in the T-shaped configuration. Molecular dynamic simulations validate the diffraction peak assignments. The linear rheology of PVBP samples reveals a thermorheologically simple response and a very low value of G_N⁰ (0.065 MPa). This is consequence of the low chain flexibility, which also explains the relatively high entanglement molecular weight value for PVBP (58.3 kg/mol).

中文翻译：

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聚（4-乙烯基联苯）的分子结构，链大小和线性流变学

使用广角X射线散射（WAXS），小角中子散射（SANS）研究了一系列多分散性范围为1.08至2.75的聚（4-乙烯基联苯）（PVBP）样品的线性粘弹性和分子结构。和流变学测量。PVBP链的尺寸（例如统计段长度，持久性长度和装箱长度）是从SANS测量获得的。由于联苯单体的体积大，PVBP在最常见的热塑性塑料（包括聚苯乙烯和聚乙烯基环己烷）中具有最低的链柔韧性和最大的毛细管直径。尽管如此，PVBP如下的弹性模量和包装长度（之间的通用电源律关系ģ _Ñ ⁰ α p ^-3）。PVBP的X射线衍射包括两个主要的无定形峰：一个与链间（主干）相关性相关，另一个由苯基-苯基相关性引起。后者是由于苯环的π–π堆积，主要是排列成T形。分子动力学模拟验证了衍射峰的分配。PVBP样品的线性流变显示出热流变简单的响应和非常低的G _N ⁰（0.065 MPa）值。这是低链柔性的结果，这也解释了PVBP的相对较高的纠缠分子量值（58.3 kg / mol）。