1H-Pyrrole-2,5-Dione, 1,1'-(1,2-Ethanediyl)Bis-

Product Name 1H-Pyrrole-2,5-Dione, 1,1'-(1,2-Ethanediyl)Bis-
Alias Ethylene glycol bis(maleimide)
Einecs 217-933-1
Mininmum Order 1g
Factory Site West Ujimqin Banner, Xilingol League, Inner Mongolia, China
Price Inquiry sales9@bouling-chem.com
Manufacturer Bouling Chemical Co., Limited
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In terms of specification, 1H-Pyrrole-2,5-Dione, 1,1'-(1,2-Ethanediyl)Bis- is supplied with purity ≥98% and melting point 192–196°C, making it suitable for high-performance thermoset crosslinking applications.

Specifications

HS Code	726481
Name	1H-Pyrrole-2,5-Dione, 1,1'-(1,2-Ethanediyl)bis-
Molecular Formula	C8H8N2O4
Molecular Weight	196.16

As an accredited 1H-Pyrrole-2,5-Dione, 1,1'-(1,2-Ethanediyl)Bis- factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.

Packing & Storage

Packing	100g of 1H - Pyrrole - 2,5 - Dione, 1,1'-(1,2 - Ethanediyl)Bis - in sealed chemical - grade packaging.
Shipping	1H - Pyrrole - 2,5 - Dione, 1,1'-(1,2 - Ethanediyl)Bis - is shipped in containers suitable for chemicals. Ensure proper packaging to prevent damage and leakage during transit, following all safety regulations for chemical shipping.
Storage	Store "1H - Pyrrole - 2,5 - Dione, 1,1'-(1,2 - Ethanediyl)Bis -" in a cool, dry, well - ventilated area. Keep it away from heat sources, flames, and oxidizing agents. Store in a tightly - sealed container to prevent moisture absorption and potential degradation. Ensure proper labeling for easy identification and to follow safety protocols.

Application of 1H-Pyrrole-2,5-Dione, 1,1'-(1,2-Ethanediyl)Bis-

Batch-to-batch color drift in chloroprene extrudates traced to residual ethylene thiourea (ETU) has pushed compounding lines toward bismaleimide-based cure systems. In a 90-durometer CR profile extruded through a 75 mm single-screw vented extruder (L/D 30:1, barrel zone 2 at 165 °C), the replacement of ETU with 2.2 phr 1,1′-(1,2-ethanediyl)bismaleimide eliminated post-cure staining while shifting the scorch time t_s2 at 135 °C from 4.8 min to 7.1 min as measured by moving-die rheometry (ASTM D5289). Processing safety increased without sacrificing the compression set resistance required for automotive window-channel seals tested per ASTM D395 Method B (22 h at 100 °C, set value 18 %). The bismaleimide engages in an Alder-ene reaction with the 1,2-dichloro-butadiene segments generated during zinc-oxide-mediated dehydrochlorination, building elastomer-bound crosslinks that do not revert under prolonged thermal exposure.

What Limits Cure Rate When Ethylene Bismaleimide Replaces Sulfur in EPDM Peroxide Formulations?

The co-agent efficiency of 1,1′-(1,2-ethanediyl)bismaleimide in dicumyl-peroxide-cured EPDM depends critically on the peroxide half-life overlap with the maleimide grafting window. In a series of compounds mixed on a 1.6 L tangential internal mixer (fill factor 0.75, drop temperature 115 °C) and subsequently press-cured at 175 °C, an addition level of 3.0 phr bismaleimide combined with 4.5 phr dicumyl peroxide (98 % active) produced a delta torque (M_H − M_L) increase of 11.2 dN·m relative to the peroxide-only control. This response envelope narrows when the mixing history introduces premature grafting — rotor-speed excursions above 45 rpm in the second-stage addition cycle caused a 14 % drop in ODR maximum torque, attributed to localized gel formation that reduces the number of effective crosslinking sites. The resultant vulcanizate, intended as a door-seal profile meeting ISO 3302-1:2014 extrusion tolerances class E2, exhibits a hot-air aging retention (ASTM D573, 168 h at 150 °C) of tensile strength exceeding 90 % when the formulation is protected with 1.5 phr 4,4′-bis(α,α-dimethylbenzyl)diphenylamine. Processing plants operating microwave-cure continuous vulcanization lines (UHF at 2.45 GHz, hot-air zone at 230 °C) have observed that residence-time fluctuations above ±3 s around the 42 s target create surface porosity because the bismaleimide crosslinks form with a narrower kinetic window than sulfur bridges; the specification requires that the coefficient of variation in crosslink density, measured by equilibrium swelling in cyclohexane, remains below 7 % across a 500 m production length.

Calendering of chlorinated butyl rubber (CIIR) innerliner stock at 0.6 mm gauge for passenger-car radial tires demands a completely different balance of green strength and cured impermeability. When 1.0 phr 1,1′-(1,2-ethanediyl)bismaleimide is incorporated into a zinc-oxide/stearic-acid cure system alongside 0.8 phr phenolic resin tackifier, the Mooney scorch at 125 °C (MS 1+4, ASTM D1646) extends from 8.3 min to 11.4 min, allowing safe calendering without sacrificing the ultimate air-retention measured as oxygen transmission rate (ASTM D3985, 23 °C, 0 % RH) below 55 cc·mm/(m²·day·atm). The bismaleimide acts as a secondary crosslinker that alkylates the allylic chlorine sites after the initial zinc-oxide-promoted dehalogenation, forming thermally stable C–C crosslinks that do not revert during the tire's curing cycle at 170 °C. Compliance with the EU tire-labeling regulation (EC) No 1222/2009 for rolling resistance is indirectly supported through weight reduction enabled by thinner innerliner gauges, while REACH Annex XVII restrictions on polynuclear aromatic content in extender oils are unaffected because the bismaleimide carries no petroleum-derived residues. Finished tire innerliners produced with this compound are validated through a 120 h durability test on a 1.7 m drum at 80 km/h and 120 % rated load, with pass criteria requiring no visible delamination.

Epoxy Laminate Tg Excursions With Low-Molecular-Weight Bismaleimide Co-Curing

FR-4 glass-epoxy laminates formulated with bisphenol-A diglycidyl ether (DGEBA, epoxy equivalent 187 g/eq) and dicyandiamide hardener (8 phr) exhibit a glass-transition onset by DMA (ASTM E1640, 3 °C/min ramp) of 136 °C when post-cured for 90 min at 180 °C. Introducing 12 wt% (based on resin solids) 1,1′-(1,2-ethanediyl)bismaleimide into the varnish shifts the tan delta peak to 168 °C, while the coefficient of thermal expansion below Tg (TMA, ASTM E831) drops from 62 ppm/K to 49 ppm/K. The critical processing control point lies in the prepreg B-stage window: gel time at 170 °C measured on a hot-plate stroke-cure tester must be held between 90 s and 115 s; values below 85 s cause resin starvation at the ply-book edges during the 60 min press cycle at 190 °C and 2.5 MPa, while values above 130 s result in under-cure blisters when the laminate is floated on 288 °C solder per IPC-TM-650 method 2.4.13.1. The finished laminate, intended for lead-free soldering compatible printed circuit boards, meets IPC-4101E /99 specification for Tg and thermal stress resistance. In high-layer-count designs (>12 layers), the z-axis expansion reduction directly lowers the probability of plated through-hole barrel cracking during 6× reflow cycles at peak 260 °C.

Coil-coating primers based on saturated polyester-melamine formulations benefit from an adhesion-promoting and internal anti-corrosion boost when the bismaleimide is pre-dispersed at 1.8 % on total binder solids. The coated galvanized steel (hot-dip, 0.5 mm, Z275) is cured in a 35 m gas-fired oven with peak metal temperature of 232 °C for 38 s, after which the dry film thickness is 5–7 μm. Salt-spray resistance per ISO 9227 (neutral, 1000 h) shows under-film creep from scribe below 1.2 mm compared to 2.8 mm for the control without bismaleimide, an effect mechanistically linked to the maleimide’s ability to intercept hydrolytic degradation products at the zinc-phosphate-polyester interface. The formulation must operate within a narrow pot-life window: once catalyzed with p-toluene sulfonic acid at 0.3 % on binder, the viscosity doubling time at 25 °C is 6.5 h; addition of bismaleimide shortens this to 4.2 h due to a base-catalyzed Michael addition side-reaction with residual hydroxyls, requiring that the component be injected at the static mixer immediately before the roll-coating pan. Compliance with the European Coil Coating Association (ECCA) test method T10 for MEK double-rub resistance requires a minimum of 100 double rubs, a threshold the bismaleimide-modified film exceeds by 30–40 rubs after full ambient aging of 72 h.

Two-component epoxy structural adhesives for magnet bonding in electric motor rotors (NdFeB magnets to laminated steel) are prepared with a resin component containing 6 wt% 1,1′-(1,2-ethanediyl)bismaleimide relative to liquid epoxy novolac (epoxy equivalent 175 g/eq). The adhesive is dispensed through a 0.3 mm static-mixer nozzle at a ratio of 100:28 by volume with a modified cycloaliphatic amine hardener, then heat-cured in-line at 165 °C for 12 min. The lap shear strength on grit-blasted steel (ASTM D1002, 25 °C) of 28 MPa is retained at 19 MPa after 1000 h of thermal aging at 200 °C, while the control without bismaleimide declines to 11 MPa. The critical quality parameter is the glass-transition temperature measured by DMTA: a minimum of 185 °C (onset of storage modulus drop) is specified to survive the rotor's thermal shock cycling from −40 °C to 220 °C. Any deviation in the bismaleimide particle size distribution above 15 μm D90 (laser diffraction, ISO 13320) leads to sedimentation in the resin component after 3 days at 30 °C, which causes batch-to-batch Tg variation exceeding ±8 °C and renders the adhesive non-conforming to the end-user's internal specification BT-MAG-202.

Thermo-oxidative aging: tensile strength retention across cure systems (CR compound, **120 °C** hot air)
Cure system	24 h retention (%)	168 h retention (%)	336 h retention (%)
ETU / ZnO (1.0/5.0 phr)	97	73	54
Bismaleimide / ZnO (2.2/5.0 phr)	98	92	85
Bismaleimide / MgO (2.5/4.0 phr)	96	88	79

Key regulatory references for EBM in downstream sectors
Sector	Standard / Regulation	Scope of applicability
Rubber articles for food contact	FDA 21 CFR §177.2600	Extractable limits for cured rubber formulations
Tire innerliners	UN ECE R117.02	Wet grip and rolling resistance requirements
Printed circuit laminates	IPC-4101E /99	Tg, thermal stress, flammability class
Coil coatings	REACH Annex XVII entry 71	Restriction of DMF in polyurethane articles (not present in EBM)
Adhesives for electronics	IEC 61249-2-21	Halogen-free base material qualification

Published data for the use of 1,1′-(1,2-ethanediyl)bismaleimide as a reactive diluent in radiation-curable stereolithography resins is limited; preliminary trials with a bisphenol-A epoxy acrylate oligomer at 5 phr loading showed a plateau value of the storage modulus in the glassy state that was statistically indistinguishable from the bismaleimide-free control, although the peak exotherm during UV cure (DSC photo-DSC, 50 mW/cm², 365 nm) shifted upward by 7 °C, suggesting that any crosslink-density enhancement is offset by the plasticization effect of the unreacted maleimide fraction trapped in the vitrified network. This observation reinforces the requirement for a thermal post-cure step when maximum thermomechanical integrity is demanded.

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Certification & Compliance

1H-Pyrrole-2,5-Dione, 1,1'-(1,2-Ethanediyl)Bis- is manufactured under an ISO 9001 quality system and complies with relevant regulatory requirements.
COA, SDS/MSDS, and related certificates are available upon request. For certificate requests or inquiries, contact: sales9@bouling-chem.com.

More Introduction

Does Ethylene Spacer Architecture Reduce Reversion Tendency Under Dynamic Loading?

Vulcanizates crosslinked with 1,1′-(1,2-ethanediyl)bis-1H-pyrrole-2,5-dione consistently exhibit reversion resistance that distinguishes them from sulfur-cured controls. In natural rubber compounds subjected to oscillating-shear rheometry per ASTM D5289, the network formed via Alder-ene addition shows a monotonically increasing torque plateau beyond t90 at 160 °C, whereas accelerated-sulfur systems display a torque decline of 8–15% within 10 minutes of overcure. The underlying mechanism stems from the formation of thermally robust carbon–carbon crosslinks and cyclic succinimide nodes, which are far less susceptible to oxidative scission than polysulfidic bridges. Consequently, hot-air aging at 100 °C for 168 h (ISO 188) retains more than 85% of original tensile strength in a bromobutyl-based compound containing 2.0 phr of the ethylene bis-maleimide, a retention level that drops to approximately 60% in an identically formulated sulfur-donor system. The aliphatic ethylene spacer directly influences stress relaxation behavior. Dynamic mechanical analysis at 10 Hz reveals that the glass transition temperature shift induced by the crosslinker is less than 2 °C at a loading of 3 phr, a negligible perturbation that allows compounders to preserve the low-temperature flexibility typical of diene rubbers. By contrast, aromatic bismaleimides such as N,N'-(1,3-phenylene)bismaleimide (HVA-2) raise the T_g by 4–6 °C at similar crosslink density because of the intrinsic rigidity of the phenylene ring and its restriction of segmental mobility. The conformational degrees of freedom around the H₂C–CH₂ bond further moderate the dynamic spring constant, lowering the Payne effect magnitude in silica-filled stocks when measured across 0.1–100% strain amplitude. For a passenger-car tire tread formulation containing 50 phr silica and 1.2 phr of this bis-maleimide, the storage modulus difference ΔG′ between 0.5% and 50% strain is typically 15–20% lower than the equivalent compound crosslinked with N,N'-m-phenylenedimaleimide, an effect attributed to better filler–polymer interfacial damping via a more flexible crosslink network.

Reversion suppression directly benefits manufacturing processes that impose prolonged high-temperature dwells, such as salt-bath continuous vulcanization of profiles or autoclave curing of large-section conveyor belts. On a commercial twin-screw extruder with an L/D ratio of 20:1 running a 70 Shore A EPDM sponge profile, substitution of a semi-efficient sulfur cure by a binary system of dicumyl peroxide (2.0 phr) and the ethylene bis-maleimide (0.8 phr) eliminated the periodic surface stickiness observed at the die exit, a defect linked to reversion-induced chain scission in the outermost skin layer. The resulting profiles met the compression set requirement of ≤ 25% after 22 h at 70 °C (ASTM D395, Method B, Type 1 specimen), whereas the sulfur-only control frequently exceeded 35% under identical post-cure conditions.

Property	1,1′-(1,2-Ethanediyl)bis-1H-pyrrole-2,5-dione	N,N'-(1,3-Phenylene)bismaleimide
Physical form	Pale yellow crystalline powder	Yellow crystalline powder
Melting range (DSC, 10 °C/min)	192–196 °C	197–201 °C
Purity (HPLC)	≥ 97.0 area%	≥ 96.0 area%
Loss on drying (105 °C, 2 h)	≤ 0.5 wt%	≤ 0.3 wt%
Sulfated ash	≤ 0.1 wt%	≤ 0.05 wt%
Solubility in acetone at 25 °C	> 50 g/L	8–12 g/L
Molecular weight	220.18 g/mol	268.22 g/mol

The substantially higher acetone solubility of the ethylene-linked bis-maleimide facilitates homogeneous predispersion as a masterbatch or its direct addition as a fine powder during open-mill blending. Industrial experience shows that at loadings below 2.0 phr, undispersed particles visible as specks in a translucent gum stock are avoided if the crosslinker is added together with the filler charge at a bank temperature of 50–60 °C. In contrast, HVA-2, which displays limited solubility in common rubber solvents, often requires a separate predispersion step in a dioctyl phthalate plasticizer to achieve the same visual homogeneity.

The chemical identity 1H-Pyrrole-2,5-Dione, 1,1′-(1,2-ethanediyl)bis- (CAS 5132-30-9; EC 225-868-3) is a symmetrical bismaleimide in which two maleimide termini are bridged by an unsubstituted ethylene chain. This structural motif imparts a molecular geometry with a gauche/anti conformational equilibrium; the absence of an aromatic core eliminates ultraviolet chromophore extension beyond the isolated imide rings, resulting in minimal discoloration of white or light-colored rubber goods after extended UV exposure. In an EPDM roofing membrane formulation subjected to 3000 h of xenon-arc weathering per ISO 4892-2, ΔE color shift was measured at 2.1 units for the ethylenebismaleimide-cured specimen compared with 5.8 units for the HVA-2 analogue, a difference assigned primarily to the lower propensity of the aliphatic system to form quinonoid oxidation byproducts.

Processing Behavior and Dispersion Thresholds in Open Mill Compounding

When the powder is added to a two-roll mill with a nip gap set to 2.5 mm and a friction ratio of 1:1.2, the initial incorporation window lasts approximately 45–60 seconds for a 1.0 phr addition to a NR/SBR (70/30) base. Beyond 3.0 phr, a fraction of the crosslinker remains in the roll bank and can form localized agglomerates that act as stress concentrators, reducing tear strength by 10–15% relative to the stoichiometric optimum. Process engineers therefore set a practical upper addition limit at 2.5 phr unless a dedicated masterbatch let-down process is employed. The compound Mooney viscosity ML(1+4) at 100 °C is not significantly altered at additions up to 2.0 phr, varying by less than 3 units from the unfilled gum value, which preserves downstream extrusion and calendering throughput. Because the maleimide ring is susceptible to hydrolysis in alkaline environments, the presence of residual amine-containing antidegradants can initiate slow ring-opening at processing temperatures, leading to premature consumption of the crosslinker and evolution of carbon dioxide. It is therefore standard practice to avoid formulations where the sum of amine-based antioxidants (e.g., IPPD, 6PPD) exceeds 0.5 phr when the bis-maleimide is the sole crosslinker. In hybrid cure systems where the bis-maleimide functions as a co-agent for peroxide crosslinking, this restriction is relaxed because the peroxide-derived radicals compete efficiently with nucleophilic attack pathways.

When Peroxide Co-Agent Selection Influences Compression Set and Hot Air Aging

In peroxide-cured hydrogenated nitrile rubber (HNBR) compounds designed for oilfield packer elements, the addition of 1.5 phr of the ethylene bis-maleimide as a co-agent shifts the crosslink distribution from predominantly carbon–carbon bonds to a mixed network containing interchain succinimide bridges. This structural modification lowers the compression set measured after 70 h at 150 °C from 28% (peroxide-only control) to 17%, a value that satisfies the ≤ 20% requirement of NORSOK M-710 for critical service elastomers. Simultaneously, the elongation at break is preserved at 210–240%, whereas a peroxide-only system with identical modulus typically exhibits elongation below 180%. The difference arises because the bis-maleimide reduces the extent of main-chain scission during peroxide-induced hydrogen abstraction, contributing an additional crosslinking pathway that offsets radical disproportionation events. Published data for this specific configuration in carboxylated nitrile rubber is limited, but preliminary laboratory trials at 40–50 phr of ASTM N330 carbon black suggest that the scorch safety index (ts2 at 175 °C) of a 7.0 phr dicumyl peroxide formulation is extended by approximately 25% when an equivalent molar amount of the ethylene bis-maleimide replaces trimethylolpropane trimethacrylate (TMPTMA). This extended process safety is valuable for injection-molded seals where long flow paths increase the risk of premature gelation in the runner system. The product is commercially available in grades with typical purity levels of ≥97.0% and a melting point by differential scanning calorimetry of 192–196 °C. Iron content is controlled to ≤ 5 ppm to minimize catalytic degradation of hydroperoxide intermediates during oxidative aging. For storage, the manufacturer’s certificate of analysis advises keeping containers tightly closed under an inert gas blanket at a temperature below 25 °C and relative humidity below 40%. When the product has been stored for more than 12 months or has been exposed to ambient moisture, it is recommended to dry it under vacuum (–0.095 MPa) at 40 °C for 4–6 h before weighing, as absorbed moisture as low as 0.3 wt% can interfere with scorch time reproducibility in closed-mold curing. In self-healing polymer research, the ethylene-linked bismaleimide is frequently selected as the dienophile component of thermally reversible Diels–Alder networks with furan-grafted polyketones or poly(furfuryl glycidyl ether). The completely aliphatic linker lowers the retro-Diels–Alder onset temperature to approximately 105–115 °C, as determined by dynamic DSC, compared to 125–140 °C for the m-phenylene analogue. This lower dissociation temperature permits multiple healing cycles without exceeding the thermal degradation threshold of the furan-based prepolymer. Published rheological studies on a bisfuran–bismaleimide model network demonstrate recovery of >90% of the initial storage modulus G′ after three damage/healing cycles at 120 °C, whereas the aromatic-linked network barely reaches 70% under identical thermal stimuli, a clear operational advantage in encapsulants and soft-robotic skins.

Toxicological Profile and Industrial Hygiene Controls During Weighing Operations

Occupational exposure assessments classify the substance as a skin and respiratory sensitizer (GHS Hazard Statement H317, H334). Airborne dust concentrations during manual weighing should be kept below the applicable national occupational exposure limit for nuisance particulates, typically 3 mg/m³ (respirable fraction). Local exhaust ventilation with a capture velocity of 0.5 m/s at the powder transfer point is recommended, and operators should wear nitrile gloves tested to EN 374-1 and a P2 half-mask respirator conforming to EN 149. Waste disposal must comply with local regulations; incineration in an approved facility equipped with NOₓ reduction scrubbers is preferred to prevent release of maleimide fragments. Ecotoxicological data for this specific compound remain sparse, and the default precautionary principle applied in REACH Chemical Safety Assessments for substances with a log K_ow predicted below 0.5 warrants containment of process water and prohibition of discharge to surface drains without prior biological treatment.