Polyether Copolymers for

Article Cite This: ACS Appl. Polym. Mater. 2019, 1, 1540−1546

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α,ω-Bis(trialkoxysilyl) Telechelic Polyolefin/Polyether Copolymers for Adhesive Applications Using Ring-Opening Insertion Metathesis Polymerization Combined with a Chain-Transfer Agent Cyril Chauveau,† Stéphane Fouquay,‡ Guillaume Michaud,§ Frédéric Simon,§ Jean-François Carpentier,*,† and Sophie M. Guillaume*,† †

Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) − UMR 6226, F-35000 Rennes, France BOSTIK S.A., 420 rue d’Estienne d’Orves, F-92705 Colombes Cedex, France § BOSTIK, ZAC du Bois de Plaisance, 101 Rue du Champ Cailloux, F-60280 Venette, France

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‡

S Supporting Information *

ABSTRACT: Monocomponent alkoxysilyl telechelic rigid polyolefins incorporating soft polyether segments along the backbone are valuable adhesives precursors. Herein, the synthesis of α,ω-bis(trialkoxysilyl) telechelic polycyclooctene (PCOE)/ poly(propylene glycol31diurethane diacrylate) (PPG*) copolymers is reported from the original combination of Ru-catalyzed ring-opening insertion-metathesis polymerization (ROIMP) with cross metathesis (CM) in the presence of bis(trialkoxysilyl)alkenes as chain-transfer agents (CTAs). The one-pot ROIMP/CM of COE and PPG* diacrylate with {(EtO)3Si(CH2)3NHC(O)OCH2CH}2 (CTAEt) as the CTA catalyzed by Grubb’s second generation catalyst selectively affords α,ω-[(EtO)3Si]2PCOE/PPG* copolymers, which show a good thermal stability and a Bingham plastic behavior, as revealed by DSC and rheology. Subsequent curing of the copolymers upon action of moisture with various catalysts unveiled wood-adhesion properties superior to those of commercial silyl-modified polymer (SMP) references. KEYWORDS: ring-opening insertion metathesis polymerization, cross metathesis, chain-transfer agent, alkoxysilyl telechelic polyolefin/polyether copolymer, silyl-modified polymer, adhesive

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INTRODUCTION Silyl-modified polymers (SMPs) refer to diverse hybrid polymers, generally polyolefins, polyurethanes (PUs), polyethers, or polyacrylates, featuring alkoxysilyl functional groups. Over the past two decades, they have been essentially exploited in the coatings, adhesives, sealants, and elastomers (CASE) industry.1−4 Upon curing, prompted by moisture from the surrounding atmosphere, polycondensation of these alkoxysilyl functions generates a dense polysiloxane 3D network, along with the liberation of alcohol. SMPs were initially designed to replace toxic isocyanate-terminated moisture-curable PUs; they were rapidly exploited by industries thanks to their good adhesion to a wide range of substrates; excellent durability; good temperature; UV resistant, fast, controlled, and foamingfree curing; lack of strong odor or staining; and reduced health concerns.5−7 SMPs are thus valuable water-based and solventfree monocomponent adhesives that are environmentally and industrially attractive. Polyolefin-based SMPs (SMPOs) have been synthesized through olefin metathesis reactions. Both ring-opening metathesis polymerization (ROMP) of cyclic olefins and acyclic diene metathesis (ADMET) polymerizations have been successfully implemented toward the elaboration of SMPOs.8 © 2019 American Chemical Society

Recently, we have reported a range of SMPOs based on various cyclic olefins prepared by ROMP combined with cross metathesis (CM), using ruthenium catalysts in the presence of various bis(trialkoxysilyl)alkenes acting as chain-transfer agents (CTAs).9−12 Indeed, telechelic polyolefins can be synthesized by tandem ROMP/CM of cyclic olefins taking advantage of the availability for chain-transfer reaction of the internal CC bonds along the growing chains. Addition to the reaction medium of a linear symmetric functional olefin, referred to as CTA, which undergoes successive CM reactions with the growing chains or with the active catalyst moiety bearing the functional group, gives rise to α,ω-chain-end functional polyolefins.13−18 In particular, cyclooctene (COE)based SMPs were prepared with high selectivities (typically less than 25 wt % of cyclic nonfunctional polycyclooctene (PCOE) side-product) and productivities (turnover numbers (TONs) up to 95 000 molCOE·molRu−1 and 5000 molCTA·molRu−1), using symmetric functional acyclic alkene CTAs, namely, {(RO)3Si(CH2)3NHC(O)OCH2CH}2 with R = Et (CTAEt) or Me Received: April 3, 2019 Accepted: May 21, 2019 Published: May 22, 2019 1540

DOI: 10.1021/acsapm.9b00311 ACS Appl. Polym. Mater. 2019, 1, 1540−1546

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ACS Applied Polymer Materials Scheme 1. One-Pot, One-Step ROIMP/CM/CTA Synthesis of α,ω-[(EtO)3Si]2-PCOE/PPG* SMPs

(CTAMe).10 The former triethoxysilyl diurethane CTA revealed to be similarly effective in the ROMP/CM preparation of α,ω-bis(triethoxysilyl) telechelic norbornene/ COE copolyolefins, with a catalytic productivity reaching TON values up to 50 000 molcomonomers·molRu−1 and 1250 molCTAEt· molRu−1, and a similar selectivity.12 In order to diversify the SMPOs and their mechanical properties, we next tackled the incorporation of “soft” polyether segments within the “rigid” polyolefin backbone. Oligo(oxyethylene) segments were already reported by Wagener and co-workers to enhance the elasticity and adhesion properties of SMPOs. The latter bis(dimethoxymethylsilyl) telechelic polyether/carbosiloxane copolymers were prepared by ADMET polymerization.19−22 Herein, we report original polyolefin/polyether-based SMPs, synthesized in one-pot, one-step, by the new ring-opening insertion-metathesis polymerization (ROIMP)/CM of COE with a diacrylate end-capped poly(propylene glycol31diurethane) (PPG*) (both reactants being industrially available), catalyzed by Grubbs’ second-generation catalyst (G2) in the presence of the above-mentioned CTAEt (Scheme 1). The ROIMP strategy was actually first established by Grubbs23 and co-workers in 2002 for the preparation of alternated copolymers. The ROIMP of cycloolefins and diacrylates24−29 was shown to proceed through first the fast ROMP of the cycloolefin followed by the slow and progressive insertion of the diacrylate within the polyolefin. Provided a stoichiometric loading of monomers, highly alternated polymers were thus formed. ROIMP favorably revealed to be tolerant to virtually any diacrylate (macro)molecules, thereby paving the way to the incorporation of functionalities along polyolefin backbones. However, besides the ADMET variant of ROIMP (referred to as alternating diene metathesis polycondensation, ALTMET)30−34 along with an example of a tandem ROMP/ADMET,35 there is, to our knowledge, no previous work mentioning a ROIMP combined with a CTA strategy.

order to comply with industrial requirements, including, in particular, a simple and direct approach from commercially available reagents to ultimately provide polyolefin-based SMP materials with enhanced adhesion properties. Thus, the direct one-pot, one-step ROIMP/CM of COE and diacrylate endcapped PPG* catalyzed by G2 in the presence of CTAEt was investigated (Scheme 1). CTAEt was selected for its good reactivity in ROMP/CM, as above-mentioned,10−12 and also for its inability to react with the PPG* diacrylate moieties (as observed experimentally and most likely resulting from their electron-deficient-type of alkenes),36 which implies that it can only cap PCOE moieties, thereby simplifying the spectroscopic characterizations. PPG* (Mn,SEC = 2250 g·mol−1) was selected to introduce in the reaction medium a few acrylate functions relative to the propylene glycol diurethane segment length. Also, besides featuring the desired ether segments, PPG* provides urethane functions which are aimed at strengthening the final material through intra- and intermolecular hydrogen bondings and, thus, eventually enhancing the mechanical and consequently the adhesive properties of the (cured) polymer material.37,38 The reaction was conducted in a concentrated reaction medium ([COE]0 + [PPG*]0 = 6 M, [G2]0 = 0.1 mol %; 40 °C, 20 min, then 80 °C, 24 h; Scheme 1, Table 1) affording the corresponding SMPs, referred to as PCOEx/ PPG*y-CTAz (with x, y, z = weight fraction of PCOE, PPG*, and alkoxysilyl chain end-groups, respectively, x + y + z = 100 wt %). High acrylate (84−100%) and CTAEt (87−100%) conversions were reached; slightly lower conversions were observed at higher CTA loadings, likely reflecting partial catalyst deactivation under these more demanding conditions. Concomitant release of ethylene testifying of CM between acrylate and ring opened COE units was observed. Fairly good incorporation of triethoxysilyl end-groups (41−68%) and rather limited isomerization ([vinyl]/[isom] = 0.51−1.08) were observed. The difference between the Mn,SEC and Mn,theo data most likely just results from the difference between the hydrodynamic radius of PCOE/PPG* copolymers and of polystyrene standards used for the calibration.9−12,39−41 Noteworthy, the Mn,SEC values proportionally increased with the consumption of COE. Relatively high Mn,SEC values

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RESULTS AND DISCUSSION A straightforward route toward the preparation of α,ωbis(triethoxysilyl) telechelic PCOE/PPG* copolymers to be ultimately assessed as adhesive components was sought in 1541


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Reaction conditions: CH2Cl2, 20 min at 40 °C under an argon flow, then 24 h at 80 °C under vacuum. bSMPs referred to as PCOEx/PPG*y-CTAz (with x, y, z = weight fraction of PCOE, PPG*, and alkoxysilyl chain end-groups, respectively, x + y + z = 100 wt %). cMass ratio. dDetermined by 1H NMR spectroscopy; note, that the amount of ethylene is underestimated. eTheoretical molar mass calculated from the formula Mn,theo = {([COE]0 × MCOE × convCOE) + ([PPG*]0 × MPPG* × convPPG*) + ([CTA]0 × MCTA × convCTA)}/{([PPG*]0 × convPPG* × (1 − releasedethylene)) + ([CTA]0 × conv CTA)}, with MCOE = 110 g·mol−1, MPPG* = 2400 g·mol−1, MCTAEt = 582 g·mol−1, and MCTAMe = 498 g·mol−1. Quantitative COE conversion as determined by 1H NMR analysis. fNumber-average molar mass (Mn,SEC) and dispersity (ĐM = Mw/Mn) values determined by SEC vs polystyrene standards in THF at 30 °C (uncorrected Mn values). gThe corresponding 1H NMR spectrum is reported in Figure S8, which is in agreement with previously reported data.10 hCTAMe was used instead of CTAEt.10

4 4 0 8 16 19 11 42 89 96 100 84 99 91 93 100 87 95:0:5 47:31:22 50:35:15 56:37:7 50:35:15 100:0:1:0.05 11.7:0.361:1:0.012 19.4:0.6:1:0.02 41.3:1.3:1:0.043 13.3:0.41:1:0.014 α,ω-[(EtO)3Si]2-PCOE, PCOE47/PPG*31-CTAEt22 PCOE50/PPG*35-CTAEt15 PCOE56/PPG*37-CTAEt7 PCOE50/PPG*35-CTAMe15 1 2 3 4 5h

(9700−18 300 g·mol−1) were measured while maintaining a dispersity of ĐM = 2.1; in spite of the presence of some oligomers (Figure S1; most likely PCOE), which cannot originate from unreacted PPG* (Figure S2), this hinted at a low macromolecular diversity. As expected, lower loadings of CTAEt increased Mn,SEC values (compare entries 2−4). The trimethoxysilyl functional CTAMe = {(MeO)3Si(CH2)3NHC(O)OCH2CH}2 (Figure S3) was also used to probe the influence of triethoxy- vs trimethoxy-silyl functions (vide infra) and gave essentially similar conversions in CTAMe and acrylate groups (PCOE50/PPG*35-CTAMe1, entry 5). 1D and 2D 1H and 13C NMR spectroscopic analyses (Figures 1 and S4−S6) of the isolated copolymers evidenced the presence of the typical resonances of hydrogen and carbon atoms of COE units (HA−D, CA−D), PPG* units (HJ‑P,j,k, CJ‑T,j,k,t),42 COE−PPG* sequences (HE−I,CE−I), along with the CTA functional end-groups (Ha−i, Ca−e,g−i,s). In addition, resonances for vinyl (Hn) and CC isomerized (Hp−r, Cp−r) moieties were observed. On the other hand, only traces of acrylate resonances (Hl,m) were detected. These analyses supported the formation of α,ω-[(EtO)3Si]2-PCOE/PPG*, as further corroborated by FTIR spectroscopy (Figure S7). Thermal and rheological analyses of several PCOEx/PPG*yCTAz SMPs were investigated (Tables 1 2, and 3). This enabled probing the impact on adhesion properties of the alkoxysilyl function; the comonomer ratio, i.e., the polyolefin/ polyether balance; and the nature of the CTA and its weight fraction (Tables 2 and 3). All the α,ω-[(EtO)3Si]2-PCOE/PPG* copolymers displayed a two-step degradation behavior under inert atmosphere. This was assigned to first the degradation of the PPG* segments (ca. 220−290 °C) and the subsequent degradation of PCOE segments (ca. 290−480 °C). Higher loadings of CTA, and thus higher contents of trialkoxysilyl chain-ends, disfavored the copolymer thermal stability, with degradation of PCOE moieties taking place at a lower temperature (Table 2, entries 3−5; Figure S9, left). Surprisingly, PCOE50/PPG*35-CTAMe15, with trimethoxysilyl functions, displayed a significantly higher thermal stability than the triethoxysilyl end-capped alike copolymer (Table 2, entry 3), close to that of a pristine PCOE (Td10,20% = 374 and 419 °C vs 270 and 325 °C vs 406 and 425 °C, respectively; Table 2, entries 2,3,6; Figure S9, right). One cannot rule out that the Si(OMe)3 functions, which are much more reactive than Si(OEt)3 ones, were possibly polycondensing in part prior to the TGA analysis upon the action of adventitious moisture. Thus, the resulting Si(OMe)3-based polysiloxane network showed a better thermal stability than the corresponding less polycondensed triethoxysilyl-based network. Introduction of PPG* segments along the polyolefin backbone increased the glass transition temperature (Tg), as anticipated given the Tg values of the corresponding PPG* and α,ω-[(EtO)3Si]2-PCOE homopolymers (Tg = −48 to −54 vs −45 and −78 °C, respectively; Table 2, entries 3−5 vs 1 and 2), as determined by DSC (Figure S10). The α,ω-[(EtO)3Si]2PCOE/PPG* copolymers displayed crystallization (Tc) and melting (Tm) temperature values similar to those of the parent α,ω-[(EtO)3Si]2-PCOE, with yet much narrower transitions (Tc = 40 °C, Tm = 55 °C; Table 2, entries 2 vs 3−5). Larger trialkoxysilyl contents did not significantly affect the thermal transitions (Table 2, entries 4−5). All α,ω-[(RO)3Si]2-PCOE/ PPG* SMPs revealed semicrystalline copolymers, yet significantly less than α,ω-[(EtO)3Si]2-PCOE (ΔHcryst = −7 to −20

a

2.1 2.1 2.1 2.1 2.1 18 500 9700 13 000 18 300 10 200 11000 2400 3000 3900 3400 0 14 20 39 12 0 14 19 20 13 100 68 58 41 67

isom vinyl Si(OEt)3 acryl acryl CTA wCOE/wPPG*/wCTAEtc [COE]0/[PPG*]0/[CTAEt]0/[G2]0

10g

polymerb entry

convd (%)

Table 1. ROIMP/CM of PCOE, PPG*, and CTAEt Catalyzed by G2 (Scheme 1)a

released ethylened (%)

chain-endsd (mol ratio)

Mn,theoe (g mol−1)

Mn,SECf (g mol−1)

ĐMf

ACS Applied Polymer Materials

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Figure 1. 1H and J-MOD NMR spectra (400 and 100 MHz, 23 °C, CDCl3) of an α,ω-[(EtO)3Si]2-PCOE/PPG* sample isolated from the one-pot, one-step ROIMP/CM of COE, PPG* catalyzed by G2 in the presence of CTAEt (Scheme 1; Table 1, PCOE56/PPG*37-CTAEt7, entry 4).The structures depicting the polymer highlight the possible chain-end groups as shown Scheme 1.

Table 2. Thermal Characteristics of α,ω-[(EtO)3Si]2-PCOE/PPG* SMPs Prepared According to Scheme 1 (Table 1) entry

polymer

Td10%a (°C)

Td20%a (°C)

Tgb (°C)

Tcb (°C)

Tmb (°C)

ΔHcrystb (J g−1)

1 2 3 4 5 6

PPG* α,ω-[Si(OEt)3]2-PCOE10 PCOE50/PPG*35-CTAEt15 PCOE56/PPG*37-CTAEt7 PCOE47/PPG*31-CTAEt22 PCOE50/PPG*35-CTAMe15

294 406 280 312 270 374

317 425 367 379 325 419

−45 −78 −54 −48 n.o. −52

− 40 40 40 40 52

− 56 55 55 55 65

− −111 −15 −7 −15 −20

a

Degradation temperatures determined by TGA with Tdx = temperature at which x% of mass loss occurs (refer to the Supporting Information). Glass transition (Tg), crystallization (Tc), and melting (Tm) temperatures and crystallization enthalpy (ΔHcryst) determined by DSC (refer to the Supporting Information). b

vs −111 J.g−1, respectively; Table 2, entries 2−5). Noteworthy, PCOE47/PPG*31-CTAEt22, which featured the lowest molar mass value (Mn,SEC = 9700 g·mol−1), displayed the lowest ΔHcryst value; this most likely stems from the difficulty of shorter chains to crystallize (Table 2, entry 5). Finally, PCOE50/PPG*35-CTAMe15 had the highest Tc and Tm values (52 and 65 °C, respectively), even higher than PCOEs’ values, respectively, as well as the highest crystallinity (ΔHcryst = −20 J g−1) (Table 2, entry 6). As aforementioned, with this latter trimethoxysilyl end-capped copolymer, adventitious polycondensation probably began during the DSC analysis, leading to polysiloxane networks with increased thermal characteristics.

Below their Tm, at 30 °C, α,ω-[(EtO)3Si]2-PCOE/PPG* copolymers behave as Bingham plastics; these SMPs feature a very high viscosity at a low shear rate (ηγ=0.1 = 3000−8500 Pa s) and a low viscosity at a high shear rate (ηγ=100 = 148−265 Pa s) (Table 3, entries 3−5). However, when heated above their Tm, at 60 °C, a Newtonian behavior was then systematically observed, in addition to a viscosity significantly lower than at 30 °C (ηγ=0.1 = 5−33 Pa s, ηγ=100 = 3−12; Table 3, entries 3− 5). As anticipated, regardless of the temperature of analysis, the viscosity also varied correspondingly with the molar mass of the SMPs. Regarding the PCOE50/PPG*35-CTAMe15 copolymer, it behaved as a rheofluidifying liquid when heated at 60 °C because of its high Tm (65 °C) (Table 3, entry 6). 1543


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Table 3. Rheological Characteristics of the α,ω-[(EtO)3Si]2-PCOE/PPG* SMPs Prepared According to Scheme 1 (Table 1) T = 30°Ca entry

SMP

1 2 3 4 5 6

PPG* α,ω-[(EtO)3Si]2-PCOE PCOE50/PPG*35-CTAEt15 PCOE56/PPG*37-CTAEt7 PCOE47/PPG*31-CTAEt22 PCOE50/PPG*35-CTAMe15

η

γ=0.1

(Pa s)

58 n.d.b 7200 8500 3000 n.d.c

η

γ=100

(Pa s)

33 n.d.b 265 148 245 n.d.c

T = 60°Ca rheological behavior rheofluidifying n.d.b Bingham plastic Bingham plastic Bingham plastic Bingham plastic

γ 0.1

η=

(Pa s)

n.d.b 6 33 5 152

γ=100

η

(Pa s)

n.d.b 5 12 3 13

rheological behavior n.d.b Newtonian Newtonian Newtonian rheofluidifying

Viscosity and rheological behavior as determined by viscosimetry using a Contraves Low Shear 30 viscosimeter; uncertainty = ± 5% (refer to the Supporting Information). bNot determined because the polymer is solid. cNot determined because the viscosity at 30 °C was too high for our apparatus to measure it. n.o., not observed. a

Curing of the α,ω-[(EtO)3Si]2-PCOE/PPG* copolymers was investigated using different catalytic systems classically used in industry. The first one is a mixture of the organotin(IV) catalyst Neostan (S1) and the aminosilane promoter Geniosil (GF9) (Figure S11).4,43,44 In addition, more recently studied catalysts, namely, Al(acac)3 (K-KAT 5218),45 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU),46 and BF3·ethylamine were also investigated.46,47 Preliminary screening of the efficiency of these curing catalysts was performed on PCOE47/PPG*31-CTAEt22 and PCOE50/PPG*35-CTAMe15 (Figure 2). Adhesion of cured SMPs on wood pieces was

performs better with trimethoxysilyl functions. On the other hand, the catalytic system [1 wt % DBU + 0.1 wt % BF3·EA] remained poorly effective. K-KAT 5218 did not correctly cure the ethoxysilyl groups, even when associated with the promoter GF9, and showed slightly better results with methoxysilyl groups. These initial results demonstrated that, under our operating conditions, the traditional organotin-based catalyst S1/GF9 worked best, and that this easy-to-handle catalyst is efficient under simple conditions. Optimization of these preliminary results (e.g., catalyst loading, temperature of application, curing conditions, etc.) shall undoubtedly improve the properties of the final materials. The investigation of adhesive properties of the S1/GF9cured SMPs was extended to other PCOEx/PPG*y-CTAz copolymers. The results were benchmarked with Polyvest E100, a polybutadiene-based SMP functionalized with triethoxysilyl functions, commercialized by Evonik as a readyto-use adhesive (Figures S13 and S14). Polyvest E100 exhibits a strain-at-break value of 2.6 MPa, which is typical for SMP industrial adhesives (Figure 3). The cured PCOE56/PPG*37-

Figure 2. Strain-at-break of wood-adhesives prepared from (blue square) PCOE47/PPG*31-CTAEt22 and (orange square) PCOE50/ PPG*35-CTAMe cured with several catalytic systems (refer to the Supporting Information for details).

evaluated upon rapidly spreading out a freshly prepared mixture of the catalytic system and the SMP copolymer onto a wood piece, followed by counter-applying an identical wood piece and ultimately allowing curing in a controlled atmosphere (44% moisture) at 25 °C for 7 days (Figure S12). Noteworthy, the use of GF9 as a promoter in combination with S1 improved by nearly 300% the adhesion. The catalytic system [1 wt % S1 + 1 wt % GF9] was revealed as the most efficient, with both (EtO)3Si− and (MeO)3Si− SMPs displaying strain-at-break values up to 4.7 and 6.2 MPa, respectively. DBU was the second most effective catalyst with a similar strain-at-break (3.8 and 3.9 MPa) regardless of the nature of the trialkoxysilyl group. These results suggest that DBU catalyzes the polycondensation of both triethoxysilyl and trimethoxysilyl groups to a similar extent, while S1/GF9

Figure 3. Strain-at-break of cured PCOE/PPG* SMP adhesives on wood benchmarked with Polyvest E100. All samples were cured with 1 wt % S1 + 1 wt % GF9.

CTAEt7 and PCOE47/PPG*31-CTAEt22 copolymers revealed better adhesive properties than PCOE50/PPG*35-CTAEt15. The superior strain-at-break of PCOE47/PPG*31-CTAEt22 most likely originates from the higher content of triethoxysilyl chain-ends, resulting in more entanglements that promote a higher resistance to strain. The results obtained with PCOE56/ PPG*37-CTAEt7 possibly arose from the increased average molar mass (Mn,SEC = 18 300 g·mol−1 vs 13 000 g·mol−1 for PCOE50/PPG*35-CTAEt15) which consequently improved the 1544


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(3) Mittal, K. L.; Pizzi, A. Handbook of Sealant Technology; CRC Press: Boca Raton (FL), 2009. (4) Pizzi, A.; Mittal, K. L. Handbook of Adhesive Technology; CRC Press, Taylor & Francis Group, 2017. (5) Chruściel, J. J.; Leśniak, E. Modification of Thermoplastics with Reactive Silanes and Siloxanes, in Thermoplastic Elastomers; Adel ElSonbati, Ed.; InTech, 2012; Chap 9, p 155−192. (6) Owen, M. J.; Dvornic, P. R. Advances in Silicon Science; Springer, 2012; Vol. 4. (7) Lee, L. H. In Adhesion Science and Technology; Plenum Press: New York, 1975. (8) Guillaume, S. M. Advances in the synthesis of silyl-modified polymers (SMPs). Polym. Chem. 2018, 9, 1911−1926. (9) Diallo, A. K.; Michel, X.; Fouquay, S.; Michaud, G.; Simon, F.; Brusson, J.-M.; Carpentier, J.-F.; Guillaume, S. M. α-Trialkoxysilyl Functionalized Polycyclooctenes Synthesized by Chain-Transfer RingOpening Metathesis Polymerization. Macromolecules 2015, 48 (20), 7453−7465. (10) Michel, X.; Fouquay, S.; Michaud, G.; Simon, F.; Brusson, J.M.; Carpentier, J.-F.; Guillaume, S. M. α,ω-Bis(Trialkoxysilyl) Difunctionalized Polycyclooctenes from Ruthenium-Catalyzed Chain-Transfer Ring-Opening Metathesis Polymerization. Polym. Chem. 2016, 7 (29), 4810−4823. (11) Michel, X.; Fouquay, S.; Michaud, G.; Simon, F.; Brusson, J.M.; Carpentier, J.-F.; Guillaume, S. M. Simple Access to Alkoxysilyl Telechelic Polyolefins from Ruthenium-Catalyzed Cross-Metathesis Depolymerization of Polydienes. Eur. Polym. J. 2017, 96, 403−413. (12) Michel, X.; Fouquay, S.; Michaud, G.; Simon, F.; Brusson, J.M.; Roquefort, P.; Aubry, T.; Carpentier, J.-F.; Guillaume, S. M. Tuning the Properties of α,ω-Bis(Trialkoxysilyl) Telechelic Copolyolefins from Ruthenium-Catalyzed Chain-Transfer Ring-Opening Metathesis Polymerization (ROMP). Polym. Chem. 2017, 8 (7), 1177−1187. (13) Chung, T. C.; Chasmawala, M. Synthesis of telechelic 1,4polybutadiene by metathesis reactions and borane monomers. Macromolecules 1992, 25, 5137−5144. (14) Hillmyer, M. A.; Grubbs, R. H. Preparation of hydroxytelechelic poly(butadiene) via ring-opening metathesis polymerization employing a well-defined metathesis catalyst. Macromolecules 1993, 26, 872− 874. (15) Hillmyer, M. A.; Grubbs, R. H. Chain Transfer in the RingOpening Metathesis Polymerization of Cyclooctadiene Using Discrete Metal Alkylidenes. Macromolecules 1995, 28, 8662−8667. (16) Pitet, L. M.; Hillmyer, M. Carboxy-Telechelic Polyolefins by ROMP Using Maleic Acid as a Chain Transfer Agent. Macromolecules 2011, 44, 2378−2381. (17) Bielawski, C. W.; Benitez, D.; Morita, T.; Grubbs, R. H. Macromolecules 2001, 34, 8610−8618. (18) Morita, T.; Maughon, B. R.; Bielawski, C. W.; Grubbs, R. H. A Ring-Opening Metathesis Polymerization (ROMP) Approach to Carboxyl- and Amino-Terminated Telechelic Poly(butadiene)s. Macromolecules 2000, 33, 6621−6623. (19) Matloka, P. P.; Kean, Z.; Wagener, K. B. Chain Internal/Chain End Latent Crosslinking in Thermoset Polymer Systems. J. Polym. Sci., Part A: Polym. Chem. 2010, 48 (9), 1866−1877. (20) Matloka, P. P.; Kean, Z.; Greenfield, M.; Wagener, K. B. Synthesis and Characterization of Oligo(Oxyethylene)/Carbosilane Copolymers for Thermoset Elastomers via ADMET. J. Polym. Sci., Part A: Polym. Chem. 2008, 46 (12), 3992−4011. (21) Jiang, H.; Zheng, Z.; Song, W.; Li, Z.; Wang, X. Alkoxysilane Functionalized Polyurethane/Polysiloxane Copolymers: Synthesis and the Effect of End-Capping Agent. Polym. Bull. 2007, 59 (1), 53−63. (22) Matloka, P. P.; Sworen, J. C.; Zuluaga, F.; Wagener, K. B. Chain-End and Chain-Internal Crosslinking in Latent Reactive Silicon Elastomers. Macromol. Chem. Phys. 2005, 206 (2), 218−226. (23) Choi, T.-L.; Rutenberg, I. M.; Grubbs, R. H. Synthesis of A, BAlternating Copolymers by Ring-Opening-Insertion-Metathesis Polymerization. Angew. Chem., Int. Ed. 2002, 41 (20), 3839−3841.

cohesion of the material. These results suggest that both high molar mass values for their high entanglement and cohesion, and low molar masses for their plasticizing effect, in addition to a high density of trialkoxysilyl functions, are required for an optimal adhesion. PCOE50/PPG*35-CTAEt15 really surpassed all other SMPs in terms of adhesive properties, with a strain-atbreak as high as 6.2 MPa. The presence of trimethoxysilyl functions, much more prone to hydrolysis than triethoxysilyl ones, clearly induced this outstanding result.48,49 Both PCOE47 /PPG* 31 -CTA Et22 and PCOE 50 /PPG* 35 -CTA Et15 gave strain-at-break values higher than the Polyvest E100 reference. These preliminary results are thus quite promising for the elaboration of commercially valuable SMP-based adhesives with enhanced efficiency.

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CONCLUSION Overall, these results (i) provide the first reported ROIMP/ CM combined with a CTA strategy; (ii) afford a straightforward one-step synthesis of well-characterized α,ω-[(EtO)3Si]2PCOE/PPG* copolymers from industrially available reactants; and (iii) demonstrate that the ROIMP approach, favorably tolerant to a functional diacrylate macromolecule, enables the incorporation of “soft” polyether functionalities along the “rigid” polyolefin backbone. TGA analyses evidenced that these SMPs generally exhibited high thermal stability (Td10% = 270−374 °C), suggesting a promising use as high-temperature adhesives. DSC studies showed a semicrystalline behavior with a polyether plasticizing effect. Their rheological behavior varied from Newtonian to non-Newtonian fluids. The Bingham plastic profile of SMPs synthesized by this ROIMP/CM/CTA route stands as a major advantage for adhesive applications. Adhesive properties of α,ω-[(EtO)3Si]2-PCOE/PPG*-cured materials revealed in particular a high adhesion as compared to common commercial SMPO references.

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ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acsapm.9b00311. Detailed experimental section and complementary data on the PCOE/PPG* copolymers (PDF)

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AUTHOR INFORMATION

Corresponding Authors

*E-mail: [email protected]. *E-mail: [email protected]. ORCID

Sophie M. Guillaume: 0000-0003-2917-8657 Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS Financial support of this research by Bostik (Ph.D. support to C.C.) is gratefully acknowledged. Dr. B. Colin is gratefully acknowledged for his help with the mechanical tests.

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REFERENCES

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