Thin‐film nanostructure and polymer architecture in semicrystalline syndiotactic poly(p‐methylstyrene)–(cis‐1,4‐polybutadiene) multiblock copolymers

Abstract

The thin‐film morphology of stereoregular syndiotactic poly(p‐methylstyrene)–(cis‐1,4‐polybutadiene) (sP(pMS–B)) multiblock copolymers has been investigated using tapping mode atomic force microscopy with variation of the polymer composition and monomer block lengths. The morphology of the thin films ranges from isolated circular domains of sP(pMS) embedded into a matrix of polybutadiene (PB) to isolated domains of PB embedded into a matrix of sP(pMS), passing through bicontinuous (jagged) lamellae when the pMS concentration is in the range 20–67 mol%. Multiple folding of the polymer segments, i.e. where reciprocal inclusions of polymer segments to each other phase are able to generate greater domain, has been postulated and validated by considerations on the polymer architecture and the thermal and crystalline behaviour. © 2019 Society of Chemical Industry

Highly efficient hydroamination of phenylacetylenes with anilines catalysed by gold nanoparticles embedded in nanoporous polymer matrix: Insight into the reaction mechanism by kinetic and DFT investigations

“…[7][8][9][10][11][12][13][14][15][16][17][18][19] In this work we report on the performances of the AuNPs catalyst embedded in a nanoporous semicrystalline polymer matrix consisting of syndiotactic polystyrene-cis-1,4-polybutadiene multiblock copolymer (sPSB). [20][21][22][23][24] The copolymer with composition rich in styrene (>80 wt%) makes the properties of this support similar to those of syndiotactic polystyrene where high affinity and permeability to small organic molecules were demonstrated. Actually aromatic and halogenated molecules are hosted into the nanocavities or nanochannels of the crystalline lattice of the δ and ε crystalline forms, producing co-crystalline phases or intercalates of syndiotactic polystyrene.…”

“…The catalytic tests were carried out under inert protective atmosphere (N 2 ) and dark conditions in the presence of activated molecular sieves (4A). The sPSB copolymer [20][21][22][23][24] (88 mol% of styrene (93 wt%)), the AuNPs-sPSB catalyst ([Au] = 2.0 wt%) [30][31][32][33] and aniline-N,N-d 2 [34] were synthesized and characterized according to the reported procedures. Tetrachloroauric acid trihydrate (≥49.0 wt% of Au, Sigma-Aldrich), sodium triethylborohydride (1.0 M in THF; Sigma-Aldrich), phenylacetylene (PA; 98%; Sigma-Aldrich), aniline (AN; 98 %; TCI Chemicals), p-toluidine (99 %; Sigma-Aldrich), 4-chloroaniline (98 %, Sigma-Aldrich), 2,4,6-trimethylaniline (98 %, Sigma-Aldrich), 4bromoaniline (97 %, Sigma-Aldrich), 1-bromo-4-ethynylbenzene (97 %, Sigma-Aldrich), 4ethynylanisole (97 %, Sigma-Aldrich), p-anisidine (>99 %, Sigma-Aldrich), 4-ethynyltoluene (97 %, Sigma-Aldrich), AuNPs-TiO 2 (1 wt% Au on titania support; Strem Chemicals), AuNPs-ZnO (1 wt% Au on zinc oxide; Strem Chemicals), AuNPs-Al 2 O 3 (1 wt% Au on aluminium oxide; Strem Chemicals), AuNPs-CB (1 wt% Au on amorphous carbon black support; Strem Chemicals), gold(III) standard solution for analysis ICP-OES of AuNPs-sPSB (1.000±0.002 g/L of gold in water with 2 wt% of HCl; Carlo Erba Reagenti) and deuterated solvents (Sigma-Aldrich or Eurisotop) were used, unless otherwise stated, as received.…”

Synthesis and Tuning of Gold Nanoparticles Supported on Polymorphic Semicrystalline Nanoporous Polymer for Catalytic Aerobic Oxidation of Alcohols

“…[13] Microencapsulation of naked AuNPs in covalently crosslinked polystyrene [8] yielded one of the most efficient gold nanocatalysts suitable in a wide range of organic transformations such as aerobic oxidation of alcohols, direct synthesis of esters, amides via aerobic oxidative reaction couplings. [14] In previous studies, we investigated the catalytic performance of AuNPs embedded in a nanoporous crystalline polymer matrix consisting of syndiotactic polystyrene (sPS) [15][16][17][18][19][20] or of multiblock copolymer with 1,3-butadiene, i. e., syndiotactic polystyrene-co-cis-1,4-polybutadiene (sPSB). [5,9,[21][22][23][24][25] These gold catalysts are efficient and selective in the aerobic oxidation of alcohols [9,23,25] or aldehydes, [21] direct oxidative esterification of alcohols, [21,23,25] reduction of nitroarenes to azobenzenes, oxyazobenzenes or anilines, [22] and the coupling of phenylacetylenes with anilines to ketimines.…”

“…sPSB copolymers containing around 77 mol% of styrene (sPS 77 B) are a good compromise that assures good swelling in organic solvents and high crystallinity of the polystyrenic phase. [19] When the concentration of HAuCl 4 was tuned to obtain a gold concentration of 2 wt % in the AuNPs-sPSB catalyst, AuNPs of 4.6 � 0.5 nm (sample 6, Table 1; Figure 4a) were produced with the co-precipitation procedure. The TEM analysis of sample 6 showed a particle dimension distribution diagram with a weight average value of 7 nm (Figure 4d) and the presence of crystalline non-defective cuboctahedral particles homogeneously embedded in the polymer matrix (Figure 4c).…”

“…In previous studies, we investigated the catalytic performance of AuNPs embedded in a nanoporous crystalline polymer matrix consisting of syndiotactic polystyrene (sPS) [15–20] or of multiblock copolymer with 1,3‐butadiene, i. e., syndiotactic polystyrene‐ co ‐ cis ‐1,4‐polybutadiene (sPSB) [5,9,21–25] . These gold catalysts are efficient and selective in the aerobic oxidation of alcohols [9,23,25] or aldehydes, [21] direct oxidative esterification of alcohols, [21,23,25] reduction of nitroarenes to azobenzenes, oxyazobenzenes or anilines, [22] and the coupling of phenylacetylenes with anilines to ketimines [24] .…”