Synthesis and Microphase Separation of PS‐b‐P(MA‐alt‐St) Block Copolymers and Their Ionomers for the Design of Polymer Crystallization Nucleation Agents

Abstract

Several well-controlled polystyrene-block -poly(styrene-alt -maleic anhydride) (PS-b -P(St-alt -MA)) functionalized block copolymers (BCs) and their sodium salt ionomers with different block ratios and molecular weights are synthesized through two-step reversible additionfragmentation chain transfer (RAFT) polymerization. The atomic force microscopy (AFM) images and differential scanning calorimetry (DSC) results reveal that the prepared BCs and their ionomers microphase separate into various nanostructures depending on the block ratios. By taking advantage of the formation of amphiphilic nanostructures via the microphase, the block ionomers serve as nucleation agents to improve the crystallization rate of poly(ethylene terephthalate) (PET). The crystallization behavior of PET upon the addition of block ionomers is investigated isothermally and non-isothermally by DSC. The results show that the block ionomers can effectively accelerate the crystallization rate of PET, which strongly depends on the molecular weights and block ratios interaction energy and the chain stretching and mainly depend on the molecular weight fraction of the constituent blocks and segregation strength denoted by χN , where χ is the Flory-Huggins interaction parameter and N is the polymerization index. [2][3][4][5] For BCs in bulk, self-assembled, periodic structures such as body-centered-cubic-packed (bcc) spheres, hexagonal-close-packed (hcp) cylinders, lamellae, and more complex phases have been theoretically predicted and experimentally observed. [5][6][7] An important application of BCs is as a compatibilizer for immiscible homopolymers. This makes the systems compatible by taking advantage of the amphiphilic characteristics to interact with both phases. For instance, functionalized BCs consisting of polar maleic anhydride (MA) units often serve as commercial compatibilizers in most immiscible polymer blends. The MA-grafted poly(styreneb -(ethylene-co -butylene)-b -styrene) block copolymer (SEBS-MA) improves the dispersion of nanomagnesium hydroxide (nano-MH) in isotactic polypropylene (PP)

In situ polymerization of poly(styrene- alt -maleic anhydride)/organic montmorillonite nanocomposites and their ionomers as crystallization nucleating agents for poly(ethylene terephthalate)

“…The T 0 m ( Table 2) was determined according to linear Hoffman-Weeks plot, which is important factor to investigate crystallization kinetics with Hoffman-Lauritzen secondary nucleation theory. In our previous work, the s e value of PET and PET/Surlyn has been calculated, which is 110.6 mJ m À2 and 47.1 mJ m À2 , respectively, indicating that the Surlyn reduce the s e of PET during the crystallization process [15]. Compared with PET and PET/OMMT, the s e values of PET/Surlyn, PET/SMA-Na and PET/IM were obviously decreased due to incorporating of ionomers as nucleating agents, indicating that ionomers are effective nucleating agents for PET, which was consistent with the results of non-isothermal crystallization.…”

“…Our recent work revealed that poly(styrene-alt-maleic anhydride) (SMA) ionomers (SMA-Na, Fig. 1d) can act as nucleating agent to improve the crystallization behaviors of PET [14,15]. However, the ionomers as nucleating agents cannot provide more and larger interfaces for crystal growth compared with that of inorganic compounds.…”

Linear viscoelasticity, nonlinear rheology and applications of polyethylene terephthalate vitrimers

“…On the other hand, the viscosity of PET will drop rapidly above melting temperature, leading to quite low melt strength and difficulties in the processing of foaming, blowing, thermoforming, etc. [9][10][11][12] To make up for these shortcomings, a large number of fillers such as inorganic nanoparticles, 13,14 organic metal salt 15 and ionomers [16][17][18][19] have been incorporated in PET to advance its mechanical properties. However, this strategy only has a weak influence on enhancing the performance of PET by improving crystallization property.…”

Phosphine‐Functionalized Syndiotactic Polystyrenes: Synthesis and Application to Immobilization of Transition Metal Nanoparticle Catalysts

“…The combination of alternating and block copolymers may open interesting perspectives for mimicking natural macromolecules. To date, by using two‐step or multi‐step method in the presence of free radical and ionic initiator, a few alternating copolymer‐ b ‐polymer such as polystyrene‐ b ‐poly(styrene‐ alt ‐maleic anhydride), [5] poly(ethyl vinyl ether)‐ b ‐poly(chlorotrifluoroethylene‐ alt ‐ethyl vinyl ether), [6] poly(maleic anhydride‐ alt ‐stearyl methacrylate)‐ b ‐poly(stearyl methacrylate), [7] poly(D,L‐lactic acid‐ alt ‐glycolic acid)‐ b ‐poly(L‐lactic acid) [8] etc. were reported previously.…”