Clathrate Phases of Styrene/p‐Methylstyrene co‐Syndiotactic Copolymers

Abstract

The possible formation of clathrate phases with several different guest molecules for co‐syndiotactic random copolymers of styrene and p‐methylstyrene has been investigated. In the presence of suitable guests, like carbon disulfide and tetrahydrofuran, clathrate phases are stable for the entire copolymer composition range. However, discontinuous changes between clathrates structurally similar to those observed for syndiotactic polystyrene and syndiotactic poly(p‐methylstyrene) have been observed by wide‐angle X‐ray diffraction and differential scanning calorimetry. Wide copolymer composition ranges of stability have been observed for carbon disulfide/syndiotactic polystyrene and for tetrahydrofuran/syndiotactic poly(p‐methylstyrene) clathrates. A phase diagram including clathrate and crystalline forms of this copolymer system has been presented.

Understanding at molecular level of nanoporous and co-crystalline materials based on syndiotactic polystyrene

“…Relevant new co-crystalline and nanoporous materials are expected in the future also for other stereoregular polymers that are able to form co-crystalline phases, like e.g. syndiotactic poly-p-methyl-styrene [110][111][112][113], syndiotactic poly-p-chloro-styrene [114], syndiotactic polymethyl-methacrylate [115], or polyethylene-oxide [116,117].…”

Crystalline structure and phase transition of syndiotactic styrene‐based copolymers

“…Guerra and co‐workers synthesized syndiotactic poly[styrene‐ co ‐( p ‐methylstyrene)], St/MeSt, and studied the effects of MeSt units on the polymorphic behavior . They also investigated the formation of the clathrate phase of St/MeSt with some guest molecules such as o ‐xylene, o ‐dichlorobenzene, tetrahydrofuran and CS 2 . They reported that the bulkiness of the guest molecules affected the formation and structures of the clathrate phase of the copolymer.…”

Synthesis and Conformation of Three‐Dimensionally Ordered Macroporous Syndiotactic Polystyrene and Poly(p‐methyl styrene)

“…Sample P5 exhibits a double endothermic peak centered at 166.4 and 181.4 8C, while the latter peak can be assigned to form II. [32] Sample P6 presents a well-defined endothermic peak centered at 177.7 8C, which corresponds to form II. [32] In addition, the first heating runs of P5 and P6 show a glass transition temperature at about 100 8C.…”

“…[32] Sample P6 presents a well-defined endothermic peak centered at 177.7 8C, which corresponds to form II. [32] In addition, the first heating runs of P5 and P6 show a glass transition temperature at about 100 8C. Apart from these, no other peaks that correspond to the crystalline form transformations are observed in the thermograms of the bulk, P5, and P6.…”

“…The DSC scans corresponding to each of the samples are shown in Figure 4. The bulk sample shows an endothermic peak, centered at 196.4 8C, together with a shoulder close to 181 8C, which are attributed to the melting temperature of form IV [31] and form II, [32] respectively. Sample P5 exhibits a double endothermic peak centered at 166.4 and 181.4 8C, while the latter peak can be assigned to form II.…”