Effect of the linking positions on the benzene ring on properties of poly(silane arylether arylacetylene)s

Abstract

Three aromatic diynes with para-, meta-, and ortho-oxyphenyloxy structures and dichlorodimethylsilane were used to prepare the corresponding poly(silane arylether arylacetylene) (PSEA) resins, that is, ppp-PSEA, pmp-PSEA, and pop-PSEA, and effect of the linking positions on the benzene ring on properties of PSEA resins was explored. The results show that pmp-PSEA and pop-PSEA resins exhibit lower crystallinity but better processability as compared with ppp-PSEA resin. For the cured PSEA resins, the density increases but the maximum water uptake decreases with the change in the linking position of the benzene ring from para-position to meta-position followed by ortho-position. Cured pmp-PSEA and pop-PSEA resins possess higher mechanical property in comparison with cured ppp-PSEA resin. The cured pop-PSEA resin shows the highest flexural strength (68.4 MPa) and flexural modulus (2.75 GPa). Furthermore, three cured resins possess excellent heat resistance with the decomposition temperature (T d5 ) of over 505 C.

Poly(silylene arylacetylene)s containing hexafluoroisopropylidene with attractive mechanical properties and dielectric performance for wave-transparent composites

“…As for the PTFOSA-C, the looser molecular arrangement with increasing –CF 3 content led to lower intermolecular forces between the molecular chains and a decline of mechanical properties, in comparison to that of PFOSA-C. In addition, the flexural strength values of the PFOSA-C and PTFOSA-C are higher than those of reported poly(silylene arylacetylene)s, such as fluorinated poly(silylene arylacetylene), 28 dendritic poly(silylene arylacetylene), 14 poly(silane arylether arylacetylene)s, 20 etc. 15,19,22,23 The flexural strength values of the PFOSA-C and PTFOSA-C as compared with those reported resins along with their T d5 are depicted in Fig.…”

“…19 Li et al synthesized isomerized poly(silane arylether arylacetylene) ( ppp -PSEA, pmp -PSEA, and pop -PSEA), which improved the mechanical properties of the materials by disturbing the regularity of the main chains. 20 The cured pop -PSEA resins showed high flexural strength (68 MPa). Besides, an increase in the interaction force between molecular chains is also an effective strategy to improve the mechanical properties of the produced materials.…”

High‐performance poly(methylsilane arylether arylacetylene) resins with low curing temperatures and weak secondary relaxations

“…The DSC thermograms of three PSEA-H resins are shown in Figure 3b, and the analysis results are 30,31 This is because the curing reactions include not only self-crosslinking reactions of C≡C groups but also the hydrosilylation reactions between Si H groups and C≡C groups. 34 In addition, the additional hydrosilylation reactions lead to higher exothermic enthalpies for PSEA-H resins than those for PSEA-M resins (e.g., 457.6 JÁg À1 for pop-PSEA-H vs 313.3 JÁg À1 for pop-PSEA-M).…”

“…As mentioned above, although several isomeric poly(dimethylsilane arylether arylacetylene) (PSEA-M) resins demonstrated high mechanical properties and thermal stability, 30,31 they showed strong secondary relaxation. In this paper, reactive Si-H groups are introduced into the chains of PSEA resins, and three poly(methylsilane arylether arylacetylene) (PSEA-H) resins (see Figure 1) are prepared to weaken the secondary relaxation.…”

“…The structures of PSEA-H and PSEA-M resins. 30,31 pmp-, pop-, and mmm-PSEA-H resins were obtained by the Grignard reactions with yields of 93%, 92%, and 95%, respectively. The structural characterization of PSEA-H resins is conducted by 1 H-NMR and FT-IR spectroscopies.…”