# A Straightforward and Rapid Method to Assess ROMP Performance in Neat Thermosetting Resins

Benjamin Godwin, Dylan Bouëtard, Jakub Talcik, Antonio del Vecchio,
Fanny Morvan, Thierry Roisnel, Marc Mauduit, Jeremy E Wulff

► To cite this version:

Benjamin Godwin, Dylan Bouëtard, Jakub Talcik, Antonio del Vecchio, Fanny Morvan, et al. A Straightforward and Rapid Method to Assess ROMP Performance in Neat Thermosetting Resins. ACS Applied Polymer Materials, 2024, 7 (1), pp.377-385. 10.1021/acsapm.4c03249. hal-04867287

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Distributed under a Creative Commons Attribution 4.0 International License
A Straightforward and Rapid Method to Assess
ROMP Performance in Neat Thermosetting Resins

Benjamin Godwin¹, Dylan Bouetard², Jakub Talcik², Antonio Del Vecchio², Fanny Morvan²,

Thierry Roisnel², Marc Mauduit*² and Jeremy E. Wulff*¹

¹Department of Chemistry, University of Victoria, 3800 Finnerty Rd, Victoria, British Columbia,
V8P 5C2, Canada

²Univ. Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, ISCR UMR 6226,
35000 Rennes, France

KEYWORDS

Olefin Metathesis, reaction-screening, ROMP, mechanical properties, thermal properties,
predicting properties.
ABSTRACT

Polydicyclopentadiene (PDCPD) is a thermosetting material used to produce body panels for industrial equipment and vehicles. PDCPD and other important thermosets are produced by direct transformation of neat monomer (dicyclopentadiene) to solid polymer using a catalyst in a process called reaction injection molding. As the polymerization and crosslinking are competitive, the polymerization process is therefore inherently challenging to study. In this work, we develop a laboratory-scale method that is rapid and low cost, and which enables the comparison of initiators for ring opening metathesis polymerization. Additionally, the method enables the prediction of both the mechanical and thermal properties of the final material.
**Introduction**

Polydicyclopentadiene (PDCPD) is an advanced engineering plastic that is used in the automotive and construction industries.¹,² Large and complex PDCPD parts are produced using a process called reaction injection molding (RIM). In RIM, a one- or two-part resin consisting of dicyclopentadiene (DCPD) monomer, various fillers (such as carbon black), additives (fire suppressants), and catalyst (or cocatalysts) are injected into a low-pressure mold, typically made from aluminum, which is maintained at a moderate temperature (typically 70–100°C).¹ Upon contact with the warm mold a highly exothermic ring opening metathesis polymerization (ROMP) reaction occurs, forming the polymer and crosslinking it simultaneously in seconds (Figure 1).³⁻⁷ This exotherm commonly reaches temperature of 200°C or more. The entire RIM cycle including injection, polymerization, and demolding typically takes around 5 minutes.¹
A

<figure><img src="image_2.png" /></figure>

<figure><img src="image_3.png" /></figure>

exothermic release of ring strain drives
competitive polymerization and crosslinking

B

<figure><img src="image_4.png" /></figure>

*crosslinks may or
may not be present in
each unit

<caption>**Figure 1.** A: Ring strain contained in the norbornene fragment of various monomers generates heat during ROMP, which drives RIM. B: Various crosslinking motifs of PDCPD triggered by the</caption>
exothermic polymerization. Note that the crosslinks are drawn on a single fragment for illustrative
purposes only. The typical crosslinking density of PDCPD is 10–15 %.⁸,⁹

Using RIM, large parts (up to 100 kg) with varying thicknesses or geometries can be made easily
and quickly. RIM is also environmentally advantageous, since its quick cycle times and low input
temperatures significantly reduce energy consumption compared to other thermosets that require
high-temperature curing.¹ The mechanical and thermal properties of these parts and therefore the
utility is heavily dictated by the catalyst system employed.¹⁰ Indeed, the only major difference
between most commercial PDCPD materials is the catalyst system used, with tungsten and
molybdenum systems both in wide use.⁴⁻⁶ Ruthenium-based systems are also becoming more
common, thanks to significant research and development in the academic world.²,¹⁰⁻¹²

Despite PDCPD's widespread use in the automotive and construction sectors, the material has
struggled to break into new markets.¹ This is due to several key disadvantages mainly tied to its
lack of surface functionality.¹³⁻¹⁶ PDCPD like most thermosets is not recyclable, though since the
DCPD monomer is a waste from the petrochemical industry, the polymer can be considered an
upcycled product even in its virgin form. The monomer is very odorous, and since polymerization
and crosslinking occur simultaneously any unreacted monomer ends up trapped in the polymer
matrix, giving the final product an unpleasant and persistent odor.¹,¹⁶ PDCPD has no chemical
tunability and further, a very low surface energy. This low surface energy leads to a substantial
bottleneck in the manufacturing process, as manufacturers must wait for parts to autoxidize prior
to painting and bonding.¹ To address this, we and others have synthesized several functionalized
DCPD derivatives.⁸,¹⁵⁻²⁰ Our second-generation monomer, oxaDCPD, has proven amenable to
scale-up in the laboratory and the resulting polymer (oxaPDCPD) possesses excellent thermal and
mechanical properties that surpass those of regular PDCPD.⁸ In addition, oxaPDCPD has an
immediately functionalized surface owing to the incorporation of a ketone functional group.⁸
However, this derivative and our previous-generation ester-functionalized DCPD both show
reduced reactivity with the Grubbs second-generation initiator (GC2, 1).⁸,¹⁸ We therefore desired
to seek out a more productive catalyst.

This is not, however, straightforward. The desired product, a glassy macromolecule, is completely
insoluble in all solvents and is particularly prized for its resistance to chemical attack—making
characterization methods suitable for soluble materials impractical.<sup>10,17,21,22</sup> Soluble linear and/or
nearly linear polymerizations of DCPD with a variety of catalysts are known to proceed in solution
and are characterizable using conventional methods such as <sup>1</sup>H NMR spectroscopy and gel
permeation chromatography (GPC). However, these solution-state reactions are significantly
slower, taking the better part of an hour, and are conducted at low temperatures and low
concentrations as compared to RIM reactions.<sup>8,13,23-25</sup> These in-solution reactions give products
whose mechanical and thermal properties do not reflect the those of the material made through the
neat reaction. Conventional methods for studying and comparing catalysts such as <sup>1</sup>H NMR based
kinetics therefore do not reflect those occurring during commercial reaction injection molding and
must be considered fraught with assumptions.<sup>22</sup>

This is recognized by industry, and commercially catalyst systems for RIM of PDCPD are tested
using thermograms, wherein resin is dispensed from the injector, and its reactivity is tracked as a
function of time, temperature, and sometimes viscosity.¹ We were interested to evaluate whether
this technique could be easily adapted to be rapid and lab-scale. Here we show a simple and fast
method for benchmarking ROMP catalysts and predicting their material properties in DCPD-based
resin systems in the laboratory. We also show that the peak temperature obtained during the
thermogram can be correlated to the glass transition temperature and mechanical properties of the
resulting material.

## Methods

Resin compositions are detailed in Table S2 of the Supporting Information. **Type-a** resin used dicyclopentadiene (DCPD) as received from Millipore Sigma. **Type-b** resin was prepared by melting 95.067 g (0.7191 mol) DCPD and adding 5.004 g (0.0416 mol) ethylidene norbornene (ENB). **Type-c** resin was neat oxaDCPD, synthesized as described previously.⁸ **Type-d** resin was prepared by melting 48.632 g (0.368 mol) DCPD and 54.023 g (0.370 mol) oxaDCPD together, and then adding 5.407 g (0.0449 mol) ENB. Samples for thermograms were prepared by adding 3 g of resin **a**, **b**, **c** or **d** to a 1-dram glass snap cap vial. Catalyst stock solutions were prepared such that the amount of catalyst delivered in 70 µL of stock solution was 0.005 mol% (**resin-a**, **b**) or 0.02 mol% (**resin-c**, **d**) relative to 3 g of the respective monomer. The catalyst (refer to Table S1 for molecular weights, and Table S3 for calculated masses) was added to a 1-dram glass vial and sonicated to dissolution in the corresponding amount of phenyl cyclohexane (PhCy) (volume described in Table S3). Stock solutions were used immediately upon preparation. An oil bath was preheated to 90 °C for catalysts **1–10**. To ensure rapid mixing of the catalysts, the resins were melted into a liquid prior to initiating the measurement. **Type-a** resins were heated to 40 °C to melt the monomer. **Type-b** resins required no initial heating. **Type-c** resins were heated to 70 °C to melt the monomer. **Type-d** resins were heated to 30 °C to melt the monomer mixture. A k-type thermocouple was then inserted into a 1-dram vial containing 3 g of melted resin. An Eppendorf pipette was then used to inject 70 µL of resin, and the tip was used to vigorously stir the vial for 3 seconds. The vial, now containing the active resin and thermocouple, was then rapidly lowered
into the hot oil bath. The reaction temperature was monitored and logged using the 373 K/J thermometer data logger and EnviromentalTester PC interface. The vial was removed from the bath after it had cooled 20 °C from its peak temperature or after 5 minutes, whichever occurred first. The vial and contents were allowed to cool by standing, after which the outside of the vial was wiped to remove residual oil, and the sample was cataloged for analysis.

## Results and Discussion

We tested three commercially available ruthenium initiators (Figure 2A, 1–3): the second- and third-generation Grubbs catalysts (1 and 2) which are based on N-heterocyclic carbene (NHC) ligands with N-mesityl substituents, and the first-generation Hoveyda-Grubbs catalyst (3) which contains a tricyclohexylphosphine ligand. We also tested seven prepared ruthenium initiators (Figure 2A, 4–10). Initiator 5 is a 3:7 ratio of bis-unsaturated unsymmetrical (u2)-NHC Ru-indenylidene and tricyclohexylphosphine/(u2)-NHC Ru-indenylidene, while initiators 4, and 6–10 contain cyclic alkyl amino carbene (CAAC) ligands with various substituents.²⁶⁻³⁰ All initiators were then tested with four unique monomer resins (Figure 2B, a–d), successfully manufacturing a total of thirty-one materials of a possible forty. Resin a was chosen as a benchmark material. Resin b was included as this combination of ENB and DCPD is often used in the literature as *de facto* DCPD, since it is much easier to handle owing to it being liquid at room temperature.⁹,¹⁰,²¹,²²,³³ For this same reason ENB was included in the copolymer formulation of resin d.
### A Catalyst Structures

<figure><img src="image_5.png" /></figure>

1

<figure><img src="image_6.png" /></figure>

2

<figure><img src="image_7.png" /></figure>

5

Ratio = 3:7, bis:mono

<figure><img src="image_8.png" /></figure>

General structure of 4, 6-10

<figure><img src="image_9.png" /></figure>

4

<figure><img src="image_10.png" /></figure>

6

<figure><img src="image_11.png" /></figure>

7

<figure><img src="image_12.png" /></figure>

8

<figure><img src="image_13.png" /></figure>

9

<figure><img src="image_14.png" /></figure>

10

### B Monomers & Monomer Solutions

<figure><img src="image_15.png" /></figure>

<figure><img src="image_16.png" /></figure>

<figure><img src="image_17.png" /></figure>

<figure><img src="image_18.png" /></figure>

% by weight

### C ROMP

<figure><img src="image_19.png" /><figcaption>**Figure 2.** A: Structurally diverse ruthenium initiators utilized in this study. B: Monomers used to make up resins a–d. C: General ROMP reaction.</figcaption></figure>
We compared initiators by simulating RIM with common laboratory equipment (Figure 3). We opted to use an oil bath heated to 90°C combined with a glass vial to act as a preheated mold. The vial containing the liquified monomers was rapidly inserted into the oil bath once the catalyst was injected and well mixed to simulate the rapid injection of a live resin into a mold. The subsequent reaction was monitored using a thermocouple inserted in the vial and coupled to a low-cost datalogger. Rapid mixing of the catalyst into the resin mixture was facilitated in two ways. First, by utilizing phenyl cyclohexane to dissolve the catalyst beforehand and second by ensuring that the monomer was completely melted before catalyst addition. Resin **b** was liquid at room temperature and required no preheating while resins **a**, **c**, and **d** were preheated to 40, 70 and 30°C respectively before catalyst addition to ensure the resins were fully liquified. No polymerization—or side reactions—were observed after heating for at least 5 minutes without a successful initiator (see Figure S22 for thermograms of control experiments carried out in the absence of initiator, and compare NMR spectra shown in Figures S16–S22 with those shown in Figure S2 and S69–S71).

This allowed for quick and repeatable dosing, and phenyl cyclohexane has been previously shown to be an acceptable additive for the neat polymerization of DCPD with a wide range of ruthenium-based catalysts.¹⁰
<figure><img src="image_20.png" /><figcaption>**Figure 3.** A: Block diagram of a reaction injection molding system. B: Simulated reaction injection molding setup for rapid laboratory testing. C: Representative thermograms obtained from datalogger. Thermograms obtained with resin *b* and 0.005 mol % initiator.</figcaption></figure>
In contrast to previous work done on neat thermosetting systems — including prior research from our own group — we elected not to use inhibitors in our resin compositions.⁸,¹⁰,²²

We began by testing initiators **1–10** at loadings of 0.005 mol% in resins **a** and **b**. These experiments showed large variations in peak temperature ($T_{pk}$) as shown in Figure 4. The highest $T_{pk}$ of all initiators tested was observed for initiator **5** in resin **b**. Initiator **1** generated consistent, high $T_{pk}$ values for all resin systems used. Interestingly, in resin **a** initiator **5** was outperformed by initiators **1**, **6** and **7** which all produced higher $T_{pk}$ values. We noted that for the CAAC based initiators (**4**, **6–10**) as the steric bulk of the substituents on the CAAC ligand decreased, the reactivity of the initiators generally increased. Notably, initiators **8** and **9** both reacted nearly instantaneously with resins **a** and **b** (see Figures S29 and S30), producing depressed $T_{pk}$ values as the catalyst solution did not have time to fully mix with the monomer resin. As the initiator reacted with less resin than was available due to the speed of initiation, these $T_{pk}$ values reflect a lower reaction scale than was intended and are thus suppressed. Similarly, initiator **2** (Grubbs 3rd generation catalyst), widely known for fast-initiating catalysis, also reacted nearly instantly, but owing to the decreased viscosity of resin **b**, was able to fully mix in this resin.³¹ In contrast, initiator **4**, with its rigid and bulky adamantane substituent, never exceeded the bath temperature and only produced a polymeric gel with resins **a** and **b**.
<figure><img src="image_21.png" /><figcaption>**Figure 4.** Peak temperatures achieved during simulated RIM by various initiators in different resin types at 90°C. Reactions that failed to produce exotherms above 90°C (black line) did not exceed the bath temperature. See Figures S22–S32 for complete thermograms of each catalyst and resin combination, and of c at 0.005 mol% and controls. Error bars represent standard deviation of n = 3 replicates.</figcaption></figure>

Resin c was also tested at 0.005 mol% loading initially. However, the peak temperature was consistently that of the bath temperature and no glassy products were observed for any of the initiators used (see Figures S16, S21, S23 and S24). We therefore opted to increase the catalyst
loading to 0.02 mol% which resulted in the observation of satisfactory exotherms (see Figure 4 and Figures S27 and S31). We also prepared a mixed resin (d) consisting of 5 % ethylidene norbornene (ENB), 45 % DCPD, and 50 % oxaDCPD by weight which also produced satisfactory exotherms at 0.02 mol% loading (see Figure 4 and Figures S28 and S32). It is important to note that the most active initiator is not necessarily the best for RIM. If the reaction occurs too quickly the resin will not completely fill the mold, and the part will be defective. To this end, the particularly reactive initiators **2** and **8**—which are not suitable for RIM with resins **a** and **b**—synergize well with the inhibitory effect of oxaDCPD-containing resins **c** and **d**, leading to significantly higher T<sub>pk</sub> values. Unsurprisingly, initiators that showed latent activity with resins **a** and **b** did not work at all with resins **c** and **d**. This is presumably due to chelation and inhibition of the catalyst by the carbonyl (Figure 5A).<sup>32</sup>

<figure><img src="image_22.png" /><figcaption>**Figure 5.** A: Proposed chelation and inhibition caused by inclusion of oxygen in DCPD monomers. B: Non-canonical hydrogen bonding between a lone pair on the carbonyl and the beta hydrogen of an adjacent enone. Both inter- and intra-chain interactions are believed to occur.</figcaption></figure>
The carbene fragment type of the initiator did not have a large influence on $T_{pk}$. Benzylidenes (e.g. **1**), benzylidene chelates (e.g. **6** and **7**) and indenylidene carbene-based initiators (**5**) were all shown to be capable of producing high $T_{pk}$ values; however, the worst-performing initiators were based on benzylidene chelates.

Smoke time (SMT) is a parameter used in industry to verify reactivity and useability of resins.¹ It is defined as the time between the completion of resin injection and the appearance of smoke (generated by the heat of the exotherm) at a specified temperature.¹ This differs from the commonly measured pot-life—which is similar to the ETA-1000 (time taken to reach a viscosity of 1000 mPa.s) value measured in industry—a property that measures the amount of time required to achieve critical chain entanglement wherein the resin will not flow.¹,¹⁰,¹²,²¹,²²,³³ On the other hand, SMT₉₀ measures the time required to complete the exothermic reaction.¹ We approximated the smoke time of the various resin and catalyst combinations at 90°C (SMT₉₀) as the time from the start of the thermogram to the peak of the exotherm (Figure 3C). The observed smoke times are shown in Figure 6.
<figure><img src="image_23.png" /><figcaption>**Figure 6.** Smoke times at 90°C achieved during simulated RIM by various initiators in different resin types. Reactions that failed to produce distinct exotherms are shown as *. Smoke times at 90°C (SMT<sub>90</sub>) were approximated as the time from the start of the thermogram to peak of the exotherm. See Figures S22–S32 for complete thermograms of each catalyst and resin combination, and of c at 0.005 mol% and controls. Error bars represent standard deviation of n = 3 replicates.</figcaption></figure>

While there was no well-defined relationship between catalyst structure and SMT<sub>90</sub> (because of the large number of parameters that contribute to the measured smoke time), the presence of a benzylidene chelate-type carbene was sometimes associated with a longer SMT<sub>90</sub> (e.g. in the case
of **3**, **7**, and **10**). However, the shortest observed SMT<sub>90</sub> was observed with initiator **8** in resins **a** and **b**, followed by the fast-initiating **2**. There was no well-defined correlation between T<sub>pk</sub> and SMT<sub>90</sub>. For example, initiators **6** and **7** both produced similar T<sub>pk</sub> values to initiators **1** and **5** in resin **a** and **b** but the former had much longer SMT<sub>90</sub> values. Interestingly, with resins **c** and **d** SMT<sub>90</sub> increased disproportionally for initiators with benzylidene chelate-based carbenes as compared to those with indenylidene or non-chelating benzylidene. This is likely due to the replacement of a ligand (phosphine or pyridine) capable of reversibly interacting with the catalyst by the chelating oxygen on the benzylidene fragment, thus making the active catalyst more prone to chelation by the carbonyl containing substrate in resins **c** and **d**. As in previous reports, the indenylidene-based initiator (**5**) required longer heating, and thus had a longer SMT<sub>90</sub> than the comparable benzylidene based initiator (**1**).<sup>10</sup>

To investigate the quality of our materials, we performed differential scanning calorimetry to assess the glass transition temperature (T<sub>g</sub>). A sharp exotherm in the thermogram is consistent with a high T<sub>pk</sub> value. The steepness of this exotherm is correlated with a consistent temperature of catalysis and with competitive crosslinking and polymerization, which ensures complete curing of the polymer matrix.<sup>10</sup> As shown in Figure 7, we observed a strong monotonic relationship (as assessed by Spearman's rank correlation coefficients) between the T<sub>pk</sub> and the T<sub>g</sub> of the material produced. This is true regardless of the reaction time, as even in the case of initiators **3** and **4** where the reactions were allowed to run for a full 5 minutes—as opposed to initiators that quickly produced sharp exotherms such as **1** and **5** where the total reaction time was ca. 2 minutes—the T<sub>g</sub> values are markedly lower. Refer to the SI for full experimental parameters and reaction cutoffs.

Initiator **1** produced the highest T<sub>g</sub> values for resin **a** while also recording the highest T<sub>pk</sub>. In resin **b**, initiator **5** produced the highest exotherm by a small margin and the resulting T<sub>g</sub> is also the
highest. In catalytic systems utilizing resin **d**, initiators **1, 2, 5** and **8** all produced similar $T_{pk}$ values; however the $T_g$ values are scattered.

<figure><img src="image_24.png" /><figcaption>**Figure 7.** A: $T_{pk}$ vs $T_g$ of resin **a**, with a Spearman's rank correlation coefficient ($\rho$) = 0.90. B: $T_{pk}$ vs $T_g$ of resin **b**, $\rho$ = 0.68. C: $T_{pk}$ vs $T_g$ of resin **c**, $\rho$ = 0.95. D: $T_{pk}$ vs $T_g$ of resin **d**, $\rho$ = 0.87. $T_g$ values shown for n =1 of initiator/resin combinations that produced material suitable for analysis.</figcaption></figure>
It is likely that the catalyst also plays a role in determining the specific properties of the material, perhaps by dictating polymer microstructure. Materials made using resin **c** and to some extent resin **d** displayed higher $T_g$ values relative to the $T_{pk}$ than did resins **a** and **b**. This result was consistent with expectation, since in previous work we have shown that materials made from resin **c** display markedly higher mechanical and thermal properties than those of unfunctionalized polydicyclopentadiene.⁸ This increase in performance is largely due to the presence of the polar ketone group (which can contribute dipole-dipole interactions that lead to stronger inter-chain interactions), but we also showed previously that polymers made from oxaDCPD can benefit from non-canonical hydrogen bonds between a β-hydrogen of one residue, and a carbonyl of a nearby residue (Figure 5B).⁸,³⁴⁻³⁶ The extra inter-chain interactions and strong intermolecular forces present in **c** and **b** based materials make up for a lower covalent crosslink density caused by lower $T_{pk}$ values.

The mechanical properties of a material are directly related to its $T_g$. To show this, we assessed the mechanical properties of our materials using Vickers Hardness (VH) testing. Hardness testing is an advantageous mechanical test for small scale laboratory measurements as it can be performed quickly using a very small amount of material. Additionally, no special sample geometry is required, and the test is non-destructive.³⁷ Further, because hardness is a measure of a material's resistance to plastic deformation, the tensile strength may be estimated (Table S9).³⁷⁻³⁹ The calculated tensile values are similar to what would be expected for DCPD.⁸ Some reactions that produced samples that were suitable for analysis by DSC—such as those produced by initiators **3** and **9** in resins **a** and **b**—produced materials that were too rubbery to test using Vickers Hardness and are thus excluded from this analysis. Material **5c** was also too rubbery for the VH test and materials **3d**, **6d**, and **7d** were likewise too soft to provide quality data. Figure 8 shows the results
of the VH testing displayed in MPa (see Table S7 for HV1 values). A strong monotonic relationship (once again assessed using Spearman's rank correlations) was observed between T<sub>pk</sub> and the hardness of the material made from resins a, c, and d. For resin b the relationship was weaker, but there was still a positive correlation between T<sub>pk</sub> and hardness. Materials made from resin c had generally lower hardness values (likely owing to the presence of small amounts of entrapped monomer), while resins a, b, and d were quite similar. It is likely that the hardness measurements were adversely affected by the inclusion of phenyl cyclohexane as a solubilizing agent for the catalyst.
<figure><img src="image_25.png" /></figure>

<figure><img src="image_26.png" /></figure>

<figure><img src="image_27.png" /></figure>

<figure><img src="image_28.png" /><figcaption>**Figure 8.** Vickers Hardness (VH) in MPa A: *T*<sub>pk</sub> vs VH of resin **a**, ρ = 0.6. B: *T*<sub>pk</sub> vs VH of resin **b**, ρ = 0.2. C: *T*<sub>pk</sub> vs VH of resin **c**, ρ = 0.9. D: *T*<sub>pk</sub> vs VH of resin **d**, ρ = 0.77. VH values shown for n = 3 of initiator/resin combinations that produced material suitable for analysis.</figcaption></figure>

**Conclusion**

We have developed a simple and rapid method for screening ROMP initiators in neat thermosetting resins. Using this method, we screened forty different resin and initiator combinations. Sterically smaller CAACs were found to correlate with high reactivity and T<sub>pk</sub>.
Highly reactive species, such as GC3 (1) and small CAACs like 8 and 9 were shown to be too reactive with resins a and b. However, this enhanced reactivity was useful with resins containing oxaDCPD — a resin characterized by reduced reactivity. As in previous reports, the indenylidene-based initiator (5) showed enhanced latency.¹⁰ Importantly, the glass transition temperatures and by extension mechanical properties are generally predicted by the peak temperature reached during the model RIM reaction. This work will allow researchers to quickly and cheaply screen metathesis catalysts and resins to develop robust thermosetting materials.

The rapid-screening method described herein does not completely model an industrial RIM reaction, since heat-transfer effects (which can be significant in large-scale production) are minimized due to the small scale of the experiment, and since the walls of the vessel are glass rather than aluminum. Nevertheless, the method provides a convenient means of quickly and inexpensively assessing which catalyst (and which percent loading of that catalyst) might be appropriate for a given resin. This is particularly important for resins that need to be prepared through synthesis, and which are therefore limited in supply at the early stages of a polymer development program.

## ASSOCIATED CONTENT

The supporting information is available free of charge at https:

Complete experimental details, including synthesis of monomer, CAACs, and initiators, spectra for all compounds and materials, thermograms, protocols for performing thermograms, thermal and mechanical characterizations.
# AUTHOR INFORMATION

## Corresponding Authors

**Jeremy E. Wulff** – Department of Chemistry, University of Victoria, Victoria, British Columbia V8W 3V6, Canada; Centre for Advanced Materials and Related Technology (CAMTEC), University of Victoria, Victoria, British Columbia V8W 2Y2, Canada; orcid.org/0000-0001-9670-160X; Email: wulff@uvic.ca

**Marc Mauduit** – Univ Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, ISCR UMR 6226, 35000 Rennes, France; orcid.org/0000-0002-7080-9708; Email: marc.mauduit@ensc-rennes.fr

## Authors

**Benjamin Godwin** – Department of Chemistry, University of Victoria, 3800 Finnerty Rd, Victoria, British Columbia, V8P 5C2, Canada; Email: benjamingodwin@uvic.ca

**Dylan Bouetard** – Univ Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, ISCR UMR 6226, 35000 Rennes, France; Email: dylan.bouetard@ensc-rennes.fr

**Jakub Talcik** – Univ Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, ISCR UMR 6226, 35000 Rennes, France; Email: jakub.talcik@ensc-rennes.fr

**Antonio Del Vecchio** – Department of Chemistry and Industrial Chemistry, University of Pisa, Via Giuseppe Moruzzi 13, 56124 Pisa, Italy; Email: Antonio.delvecchio@unipi.it

**Fanny Morvan** – Univ Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, ISCR UMR 6226, 35000 Rennes, France; Email: fanny.morvan@ensc-rennes.fr
**Author Contributions**

The manuscript was written through contributions of all authors. All authors have given approval
to the final version of the manuscript.

**Funding Sources**

The authors thank the Innovation for Defence Excellence and Security (IDEaS) Program of the
Canadian Department of National Defence (project IDEaS-4-1a-CP4-0299) for operating funds
that were used to support this research. Additional financial support was provided by the Natural
Sciences and Engineering Research Council of Canada (NSERC) through a Discovery grant to
J.W. M.M thanks the Agence Nationale de la Recherche (ANR-20-CE07-0030 "c-Résolu" grant
to D.B and ANR-19-CE07-0017 "ChiCAAC", grant to J.T.) and the Région Bretagne (ARED
2022 N° 2671, grant to F.M.).

**Notes**

The authors declare the following competing financial interest(s): B.G. and J.W. are co-inventors
on PCT/IB2022/052969, which claims the use of the polymer and copolymers described in this
manuscript. There are no additional conflicts to declare.

**Supporting Information**

Detailed experimental protocols, supplemental figures and tables, thermograms, X-ray crystal
structures, NMR spectra, IR spectra, hardness, TGA and DSC data.

**ACKNOWLEDGMENTS**

The authors thank Sean Adams, Chris Secord and Kody Matthews for their contributions to the
creation of the photochemical reactor. In addition, we further thank Chris Secord for assistance in
cutting samples and Ryan Mandau for hardness measurements. We also thank Vipo for the
generous gift of initiator 5.
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