1,1'-(Phenylene)Bis-1H-Pyrrole-5-Dione

The reaction between 1,1'-(Phenylene)Bis-1H-Pyrrole-5-Dione and aromatic diamines proceeds via Michael addition and subsequent chain extension, yielding a polyaspartimide backbone. Unlike condensation polyimides, this step-growth pathway liberates no volatile byproducts, enabling void-free cure of thick cross-sections exceeding 15 mm under autoclave pressures as low as 0.3 MPa. Commercial prepreg systems leverage this chemistry for hot-melt impregnation lines running at 80–100°C, where the bis-pyrrole-dione monomer acts as both chain extender and crosslinking site without the viscosity spikes characteristic of nadic-endcapped oligomers. Out-of-autoclave processing trials conducted on a 2.5 m × 1.8 m heated platen press have demonstrated laminate void content below 1.2% by volume as measured via ASTM D2734 ultrasonic C-scan, eliminating the persistent interlaminar microcracking found in condensation-cured systems when subjected to thermal cycling between -55°C and 180°C.When integrated into carbon fiber-reinforced BMI formulations at 15–25 wt% of total resin solids, the monomer modifies the cured network's crosslink density without proportionally elevating the glass transition temperature, a decoupling effect not achievable with rigid aromatic dianhydride hardeners. A multi-axial warp-knit non-crimp fabric (NCF) preform infused via vacuum-assisted resin transfer molding (VARTM) at 65°C and post-cured in a staged ramp to 230°C produced interlaminar shear strength values exceeding 82 MPa when tested per ASTM D2344 on span-to-thickness ratios of 5:1. The laminate exhibited a hot-wet compression strength retention of 83% after 72-hour immersion in 70°C distilled water, conditioned per ISO 14129. Published data for long-term creep rupture behavior in pressurized hydraulic fluid environments at 120°C is limited; however, short-term coupon-level testing indicates negligible mass uptake in Skydrol LD-4 hydraulic fluid over 500 hours.

IC Substrate Dielectric Optimization and Copper Clad Lamination Parameters

In build-up films for flip-chip ball grid array (FC-BGA) substrates with line/space geometries below 10 µm/10 µm, the bis-pyrrole-dione monomer is formulated into epoxy-silica hybrid varnishes at loadings between 8 wt% and 18 wt% on a total solids basis. The formulation serves a dual function: it reduces the dielectric dissipation factor (Df) at 10 GHz to approximately 0.0045–0.0065 as measured by the split-post dielectric resonator method per IEC 61189-2-721, while simultaneously raising the cured film's elongation-at-break to 3.8–4.5% to accommodate thermal expansion mismatches during sequential lamination cycles peaking at 200°C. Roll-to-roll slot-die coaters depositing 15–25 µm dry film thickness on 18 µm electrolytic copper foil operate optimally with a catalyzed varnish pot life exceeding 12 hours at 23°C, verified by tracking viscosity drift on a Brookfield DV2T at 20 rpm with spindle #SC4-21. Desmear following CO₂ laser via drilling at 9.4 µm wavelength employs a permanganate etch cycle of 85°C for 12 minutes; the cured network's allyl-adjacent pyrrolidone segments exhibit controlled swelling without undermining copper adhesion strength, which consistently registers above 0.65 kN/m per IPC-TM-650 2.4.9 peel test on low-profile reverse-treated copper foil.

Are Premature Exotherms and Crosshatch Adhesion Failures Linked to Titania Pigment Dispersion Quality in Coil-Coated Systems?

Thermosetting polyester backbones terminated with hydroxyl numbers between 25–40 mg KOH/g and crosslinked with hexamethoxymethyl melamine (HMMM) at a 1:6 catalyst-to-crosslinker molar ratio often suffer from insufficient solvent resistance in architectural coil coatings cured at peak metal temperatures (PMT) of 232–254°C for 45–55 seconds. Incorporating 3–7 wt% 1,1'-(Phenylene)Bis-1H-Pyrrole-5-Dione into the polyester backbone via reactive extrusion at 195–215°C through a co-rotating L/D 48:1 twin-screw extruder shifts the network architecture from a single-phase melamine-crosslinked system to an interpenetrating morphology. Post-cure dynamic mechanical analysis (DMA) in tension mode at 1 Hz from -50°C to 200°C reveals a secondary tan delta peak at 155–170°C attributable to the pyrrolidone-rich domains, which correlates with a methylethylketone (MEK) double-rub resistance exceeding 200 cycles per ASTM D5402 without substrate breakthrough on 0.5 mm hot-dip galvanized steel.A persistent manufacturing failure mode observed on high-speed roll-coating lines running at 120–150 m/min involves incipient gel particle formation when the catalyzed coating holding tank temperature inadvertently exceeds 42°C. Differential scanning calorimetry (DSC) ramped at 10°C/min under nitrogen per ASTM E1356-23 records a reaction exotherm onset at 138°C; however, adiabatic heat build-up in stagnant boundary layers near tank walls can prematurely initiate oligomerization, seeding microgels that manifest as crosshatch adhesion failures per ISO 2409 on a 0–5 rating scale, where unseeded controls score 0 and contaminated batches degrade to 2–3. Particle size analysis of unfiltered coating sampled immediately before the coating head using a Malvern Mastersizer 3000 with a liquid dispersion unit identifies problematic shoulder peaks centered at 8–15 µm, absent in stable batches.

Migration-Resistant Antioxidant Synergism During Rotational Molding of LLDPE Agricultural Tanks

Rotomolded linear low-density polyethylene (LLDPE) tanks for liquid fertilizer and pesticide storage experience oxidative embrittlement concentrated at the inner tank surface, where polymer chains contacting aggressive aqueous chemistries at sustained temperatures of 40–55°C undergo chain scission at rates that render standard hindered phenolic antioxidants insufficient due to their gradual leaching into the stored fluid. Dry-blending 0.15–0.35 phr of the bis-pyrrole-dione compound with 35-mesh ground LLDPE powder (melt index 3.5 g/10 min per ISO 1133-1:2022, 190°C/2.16 kg) prior to charging into a carousel-type rotomolder with a biaxial rotation ratio of 4:1 and oven temperature setpoint 280°C introduces graphtable nitrogen-centered radical scavenging sites covalently bound to the PE matrix via a grafting mechanism initiated by thermally generated macro-radicals during the sintering phase. Extraction tests per FDA 21 CFR 177.1520 simulating 10% ethanol and 3% acetic acid food simulants for 10 days at 40°C detect less than 0.02 mg/dm² total non-volatile residue migrating into simulant, compared to 0.5–1.2 mg/dm² for equivalent formulations using octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.The critical process vulnerability arises from incomplete particle coalescence at mold surface temperatures between 105–120°C, where the monomer's melting endotherm centered at 162°C per DSC keeps it in discrete solid particulates that disrupt polymer chain diffusion across powder grain boundaries. This phenomenon appears as a measurable reduction in the dart impact strength per ASTM D1709 Method B from a baseline of 14.5 J/mm to approximately 9–11 J/mm when the peak internal air temperature (PIAT) during processing fails to exceed 235°C for a sustained period of 90 seconds, a condition encountered on rotomolders lacking proportional-integral-derivative (PID) burner modulation. Successful grafting demands PIAT dwells exceeding 245°C for a minimum of 120 seconds, achievable only with forced-air cooling cycles carefully delayed until after the fusion plateau.

Oxidative Induction Time (OIT) Comparative Data — LLDPE Rotomolded Specimens (ISO 11357-6, 200°C, O₂ at 50 mL/min)
Additive Package	Loading (phr)	OIT Onset (min)	OIT After 90-Day Water Immersion at 60°C (min)
Neat LLDPE (control)	—	0.8	0.5
Hindered Phenolic AO 1	0.25	34.5	8.2
Phenolic + Phosphite (1:1)	0.25	41.6	12.8
1,1'-(Phenylene)Bis-1H-Pyrrole-5-Dione	0.25	28.3	24.9
Bis-Pyrrole-Dione + Hindered Phenolic AO 1 (1:2)	0.25	47.9	39.6

Coefficient of Thermal Expansion Mismatch Between Copper Traces and Underfill in System-in-Package (SiP) Modules

Capillary underfill dispensing onto multi-die SiP assemblies with a die-to-die gap of 60–100 µm and stand-off height below 25 µm demands encapsulants with a coefficient of thermal expansion (CTE) below 28 ppm/°C below the glass transition and 80 ppm/°C above it, as determined by thermomechanical analysis (TMA) per ASTM E831 at a 5°C/min ramp rate. When the bis-pyrrole-dione monomer is pre-dissolved in a bisphenol F epoxy resin at 12 wt% and catalyzed with a latent imidazole adduct activated above 120°C, the cured formulation exhibits a CTE₁ of 24.5 ppm/°C and CTE₂ of 72.3 ppm/°C at filler loadings of 62 wt% spherical silica with a median particle size (D50) of 0.5 µm. This represents a 14–18% reduction in CTE₂ compared to equivalent formulations omitting the bis-pyrrole-dione while substituting an anhydride flexibilizer, without sacrificing the viscosity requirement of 8–14 Pa·s at 25°C and 10 s⁻¹ shear rate measured on a parallel-plate rheometer per ASTM D4440.Jetting dispensers with a piezoelectric actuator frequency of 500 Hz and nozzle inner diameter of 100 µm deposit underfill dots of 0.15–0.35 mg along the die edge; the monomer's reaction exotherm and shrinkage profile during the staged cure (ramp at 3°C/min from 110°C to 165°C, hold 2 hours) were characterized by in-situ warpage metrology using a shadow moiré system at 25 µm/pixel resolution. Coplanarity deviations of the cured package measured from 25°C to 260°C reflow simulation remain within 38–52 µm, a range essential for maintaining second-level interconnect reliability in 0.4 mm pitch ball grid arrays. Pre-drying of the formulated underfill at 25°C and 35% RH for 16 hours is mandatory when ambient relative humidity exceeds 60%; failure to do so introduces hydrolytic opening of the pyrrole-dione ring, detectable as a 3–5% reduction in the normalized storage modulus at 260°C and a concomitant increase in the moisture sorption coefficient from approximately 0.32 wt% to 0.55 wt% per Karl Fischer coulometric titration of cured specimens conditioned at 85°C/85% RH for 168 hours.

Underfill Formulation Compliance Matrix — System-in-Package Encapsulation
Standard	Test Method	Requirement	Observed Range with 12 wt% Monomer
IPC/JEDEC J-STD-020E	Moisture Sensitivity Level 3	Pass after 3 reflow cycles at 260°C	No delamination per C-SAM, 0/22 units failed
ASTM E831-19	CTE by TMA, -40 to 260°C	CTE₁ < 30 ppm/°C	24.5 ppm/°C
ASTM D4440-15	Dynamic Viscosity, 25°C, 10 s⁻¹	< 15 Pa·s	8.3–11.7 Pa·s
ISO 11357-2:2020	DSC Glass Transition, Midpoint	Tg > 130°C	148–153°C
IPC-TM-650 2.4.41.2	Flexural Modulus, 3-Point Bend	> 8 GPa at 25°C	9.2–10.4 GPa

Compounding of halogen-free flame-retardant polyamide 66 for electrical connectors and circuit breaker housings operating at continuous-use temperatures of 140–160°C requires synergistic combinations of phosphinate salts and char-forming synergists that resist exudation during injection molding cycle times of 25–40 seconds at melt temperatures of 280–300°C. Formulations incorporating 2–4 wt% 1,1'-(Phenylene)Bis-1H-Pyrrole-5-Dione as a char promoter in a matrix of 65 wt% PA66 (relative viscosity 2.7 in 96% sulfuric acid per ISO 307), 30 wt% short glass fiber (chopped strand, 4.5 mm, 10 µm diameter), and 18 wt% aluminum diethylphosphinate achieve a V-0 classification at 0.8 mm thickness per UL 94 with a total flaming combustion time of ≤ 22 seconds across 5 specimens. The pyrrole-dione ring undergoes thermal conversion during the cone calorimeter exposure at 50 kW/m² irradiance per ISO 5660-1 to form a condensed aromatic char structure with an intumescent expansion ratio of 1.8–2.4:1 as measured by cross-sectional digital microscopy on quenched specimens, a mechanism that simultaneously reduces the peak heat release rate (pHRR) by 22–28% relative to control formulations lacking the monomer while suppressing the afterglow duration attributable to phosphorus flame inhibition.Die-swell behavior observed during compounding on a corotating twin-screw extruder with screw diameter 26 mm and L/D 40:1 at a screw speed of 350 rpm and throughput of 15 kg/h diverges systematically from baseline formulations, generating strand diameters averaging 3.8 mm versus the target 3.2 mm at identical draw-down ratios. Rheological assessment via capillary rheometry at an apparent shear rate of 1000 s⁻¹ and 290°C confirms an increase in the die swell ratio from 1.2 to 1.55 attributable to the oligomerization of the monomer during the 45-second mean residence time in the melt, necessitating adjustments to the pelletizer cutter speed from 1200 rpm to approximately 850 rpm to maintain pellet geometry within tolerance. Avoid combination of this char-promoting approach with amine-based hindered amine light stabilizers (HALS) at concentrations exceeding 0.2 wt% due to competitive consumption of the Michael addition sites on the bis-pyrrole-dione ring during melt processing, evidenced by a 40–50% attenuation of the desired UL 94 V-0 performance margin.

When co-monomer blending shifts the cure exotherm below 200 °C

Formulation with diallyl bisphenol A (DABA) or 2,2′-diallyl bisphenol A at molar ratios between 1:0.8 and 1:1.2 depresses the peak exotherm to 185–205 °C and broadens the processing window dramatically. In a typical RTM cycle, the blended resin is degassed at 120 °C under 10 mbar vacuum for 30 min, then injected into a mold preheated to 130 °C. The initial viscosity of 0.15–0.3 Pa·s at the injection temperature permits impregnation of 12K carbon fiber 2×2 twill weaves with fiber volume fractions exceeding 57%. Gelation occurs between 60–90 min at 130 °C, after which a step cure of 180 °C for 2 h followed by a free-standing post-cure at 250 °C for 4 h is applied. The cured neat resin exhibits a flexural strength of 132 MPa (ASTM D790-17, three-point bending, span-to-thickness ratio 16:1) and a flexural modulus of 4.8 GPa, values closely approaching those of the more chain-extended BMI-MDA/DABA system but with a 12–15 °C higher heat deflection temperature measured at 1.82 MPa (ASTM D648-18). Published data for the para-isomer in analogous DABA blends indicates a flexural modulus of approximately 5.1 GPa but requires melt temperatures above 250 °C to achieve comparable wet-out, rendering the meta isomer the practical choice for autoclave processing where excess temperature can induce uncontrolled thermal runaway in thick sections exceeding 15 mm.

Comparative thermal and rheological values for neat meta-phenylene bismaleimide versus para-phenylene isomer
Property	1,1′-(Phenylene)Bis-1H-Pyrrole-5-Dione (meta)	1,1′-(1,4-Phenylene)Bis-1H-Pyrrole-5-Dione (para)	Test method
Melting point (onset, DSC)	198–202 °C	298–302 °C	DIN EN ISO 11357-1:2017
Homopolymerization peak exotherm	258–264 °C	272–280 °C	DSC at 10 K·min⁻¹
Minimum melt viscosity at processing temperature	8–12 Pa·s at 210 °C	Not measurable below 300 °C without decomposition	Parallel-plate oscillatory rheometry
Glass transition temperature (tan δ, DMTA) after post-cure to 300 °C	367 °C	385 °C*	ASTM D7028-07(2015)
Solubility in NMP at 25 °C	42 g/100 mL	< 5 g/100 mL	Gravimetric

Comparative thermal and rheological values for neat meta-phenylene bismaleimide versus para-phenylene isomer

Property

1,1′-(Phenylene)Bis-1H-Pyrrole-5-Dione (meta)

1,1′-(1,4-Phenylene)Bis-1H-Pyrrole-5-Dione (para)

Test method

Melting point (onset, DSC)

198–202 °C

298–302 °C

DIN EN ISO 11357-1:2017

Homopolymerization peak exotherm

258–264 °C

272–280 °C

DSC at 10 K·min⁻¹

Minimum melt viscosity at processing temperature

8–12 Pa·s at 210 °C

Not measurable below 300 °C without decomposition

Parallel-plate oscillatory rheometry

Glass transition temperature (tan δ, DMTA) after post-cure to 300 °C

367 °C

385 °C*

ASTM D7028-07(2015)

Solubility in NMP at 25 °C

42 g/100 mL

< 5 g/100 mL

Gravimetric

*Value reported for a post-cure to 320 °C due to incomplete conversion at 300 °C; residual enthalpy remains above 15 J·g⁻¹.

Direct comparison with 4,4′-bismaleimidodiphenylmethane (BMI-MDA) reveals a critical divergence in moisture resistance. DMA scans conducted on water-immersed specimens (deionized water, 70 °C, 1000 h) show that the BMI-MDA network absorbs 2.8–3.2 wt% water, accompanied by a 22 °C depression in the tan δ peak temperature. The 1,1′-(phenylene)Bis-1H-pyrrole-5-dione homopolymer, in contrast, absorbs 1.6–1.9 wt% under identical conditions, with the corresponding peak depression limited to 9 °C. This differential arises from the elimination of the methylene-linked diphenyl structure, which reduces free volume elements identifiable by positron annihilation lifetime spectroscopy. Formulators targeting hot-wet compression performance per ASTM D695-15 often exploit this characteristic by utilizing the meta-phenylene BMI as the sole matrix precursor rather than as a modifier for BMI-MDA systems, although the intrinsic brittleness of the highly crosslinked network—unmodified strain to failure typically 1.2–1.8%—necessitates toughening with core-shell rubber particles or thermoplastic polyimide interleaf layers if post-impact compression strength (ASTM D7137/D7137M-17, CAI) must exceed 220 MPa.

What limits lathe-mixing cycle times in high-shear dispersion?

Processing of 1,1′-(phenylene)Bis-1H-pyrrole-5-dione in batch reactors employing planetary mixers encounters a well-defined thermal constraint: the dissipated mechanical energy during dispersion of the jet-milled powder into a diallyl bisphenol A melt raises the batch temperature at a rate of 2–4 K·min⁻¹ under a tip speed of 1.5 m·s⁻¹. Without active jacket cooling, the batch can surpass the critical 170 °C threshold within 25–35 min, triggering incipient oligomerization detectable as a gradual viscosity rise from 0.3 Pa·s to 0.6 Pa·s at 140 °C. Manufacturing facilities utilize a two-stage mixing protocol: the powder is incorporated at a jacket temperature of 110 °C over a 20 min period, then the jacket is reduced to 90 °C before addition of the radical inhibitor 4-tert-butylcatechol at a level of 200–500 ppm relative to total resin mass. This inhibitor package, critical for extending pot life to 6–8 h at 130 °C, must be fully dissolved before the second-stage degassing step; undissolved inhibitor crystals act as heterogeneous nucleation sites during cure, creating localized regions of reduced crosslink density visible in SEM micrographs of polished sections as 5–15 µm domains with a 10–15% lower Brinell hardness.

In continuous fiber placement (CFP) applications, the short melt residence time places a premium on rapid fusion. A slit-die rheometer attached to a CFP head operating at 3–5 m·min⁻¹ line speed measures the dynamic viscosity of the BMI melt blend at a die temperature of 175 °C. The formulation containing stoichiometrically balanced 1,1′-(phenylene)Bis-1H-pyrrole-5-dione and diallyl bisphenol A shows a shear viscosity of 0.8–1.2 Pa·s at a shear rate of 1000 s⁻¹, enabling tow wet-out within 0.2 s on a 12 mm contact radius heated compaction roller. Substituting BMI-MDA under identical conditions yields a viscosity of 1.5–2.0 Pa·s, attributed to the higher molecular volume of the diphenylmethane backbone. The lower viscosity of the meta-phenylene system translates directly into a reduction in void content from 2.5–3.5% to 1.0–1.5% in unidirectional carbon/PEEK hybrid laminates when assessed via acid digestion coupled with optical microscopy (ASTM D2734-16).

Specifications and batch-to-batch variance in commercial-scale production

The typical release specification for 1,1′-(phenylene)Bis-1H-pyrrole-5-dione intended for aerospace prepregging includes a maleimide equivalent weight of 134.0–134.5 g·eq⁻¹ (theoretical value 134.12), an ionic chloride content below 15 mg·kg⁻¹ extracted by boiling deionized water and quantified by ion chromatography per ISO 10304-1:2007, and a volatile loss not exceeding 0.30 wt% after 2 h at 150 °C. In production campaigns spanning 12–15 batches, the melting point interquartile range remains within 1.5 °C, and the DSC exotherm onset varies by less than 2.0 °C. One observed outlier pattern correlates with residual N,N-dimethylformamide from the synthesis step: DMF content above 80 ppm shifts the exotherm onset down by 3–5 °C and introduces a low-temperature shoulder in the DSC trace, likely due to acid-base interaction with trace maleamic acid intermediates. Therefore, a supplementary GC headspace method for residual solvent is recommended when the material is destined for electronics-grade formulations requiring dielectric constants (at 1 MHz, ASTM D150-18) below 3.2 after cure.

Release limits and typical analytical data for an aerospace-grade batch of 1,1′-(phenylene)Bis-1H-pyrrole-5-dione
Parameter	Release limit	Typical batch data (n=12)	Analytical procedure
Appearance	Yellow crystalline powder	Conforms	Visual against white standard
Melting range	198–202 °C	199.2–200.8 °C	DSC, endothermic peak onset
Maleimide equivalent weight	133.8–134.4 g·eq⁻¹	134.0–134.1 g·eq⁻¹	Titration with morpholine/DMF
Chloride (extractable)	≤ 15 mg·kg⁻¹	4–9 mg·kg⁻¹	ISO 10304-1:2007
Residual solvent (DMF)	≤ 50 mg·kg⁻¹	12–28 mg·kg⁻¹	Headspace GC-FID
Loss on drying (2 h/150 °C)	≤ 0.30 wt%	0.18–0.25 wt%	Gravimetric
Particle size D₅₀ (jet-milled grade)	4.0–6.0 µm	4.6–5.2 µm	Laser diffraction (Malvern)

Release limits and typical analytical data for an aerospace-grade batch of 1,1′-(phenylene)Bis-1H-pyrrole-5-dione

Parameter

Release limit

Typical batch data (n=12)

Analytical procedure

Appearance

Yellow crystalline powder

Conforms

Visual against white standard

Melting range

198–202 °C

199.2–200.8 °C

DSC, endothermic peak onset

Maleimide equivalent weight

133.8–134.4 g·eq⁻¹

134.0–134.1 g·eq⁻¹

Titration with morpholine/DMF

Chloride (extractable)

≤ 15 mg·kg⁻¹

4–9 mg·kg⁻¹

ISO 10304-1:2007

Residual solvent (DMF)

≤ 50 mg·kg⁻¹

12–28 mg·kg⁻¹

Headspace GC-FID

Loss on drying (2 h/150 °C)

≤ 0.30 wt%

0.18–0.25 wt%

Gravimetric

Particle size D₅₀ (jet-milled grade)

4.0–6.0 µm

4.6–5.2 µm

Laser diffraction (Malvern)

Workers handling the powder must observe an occupational exposure limit of 0.5 mg·m⁻³ (respirable fraction) in accordance with a supplier-derived internal benchmark, since fully validated TWA data under 29 CFR 1910.1000 remain unavailable. Dust extraction at the bag-dump station should maintain a face velocity of 0.5–0.8 m·s⁻¹ to prevent accumulation of submicron particulates on horizontal surfaces where thermal cycling between 20 °C and 50 °C can cause slight sublimation and redeposition of fine crystals.

Substituting 1,1′-(phenylene)Bis-1H-pyrrole-5-dione for BMI-MDA in high-temperature electrical insulation varnishes has been reported to raise the thermal endurance rating from Class H (180 °C) to Class C (200 °C and above) under the criteria of IEC 60085:2007, provided that the cured film thickness does not exceed 50 µm and the substrate is a properly primed copper or aluminum magnet wire. The determining factor is the onset of weight loss by thermogravimetric analysis (TGA, 10 K·min⁻¹, nitrogen): the meta-phenylene BMI homopolymer demonstrates a 5% mass loss at 442 °C, while a comparable BMI-MDA homopolymer reaches the same threshold near 415 °C. However, the steeper viscosity-temperature profile of the meta isomer demands tighter process control on vertical impregnation towers; oven zone temperature variation must remain within ±3 °C across a 2.5 m heated length to avoid resin migration towards the upper zone, which can create a gradient in pick-up weight exceeding 5 g·m⁻² top-to-bottom.

HS Code	556615
Chemical Formula	C12H6N2O4
Molecular Weight	242.19 g/mol
Appearance	Solid (usually a powder or crystalline solid)
Color	Varies, often pale yellow to light brown
Melting Point	Typically in the range of 260 - 280 °C
Solubility In Water	Insoluble
Solubility In Organic Solvents	Soluble in some polar organic solvents like DMSO, DMF
Density	Approximately 1.5 - 1.6 g/cm³
Odor	Odorless or very faint odor
Stability	Stable under normal conditions, but may decompose on heating or under strong acidic/basic conditions

Packing	500g of 1,1'-(Phenylene)bis - 1H - Pyrrole - 5 - Dione in a sealed, chemical - resistant bag.
Shipping	1,1'-(Phenylene)bis - 1H - Pyrrole - 5 - Dione is shipped in well - sealed containers, compliant with chemical transportation regulations. Special care is taken to prevent exposure, with proper labeling for hazard awareness during transit.
Storage	1,1'-(Phenylene)bis - 1H - Pyrrole - 5 - Dione should be stored in a cool, dry place. Keep it away from heat sources, flames, and oxidizing agents. Store in a tightly - sealed container to prevent moisture absorption and potential reactions. It is advisable to store it in a well - ventilated area, away from incompatible substances to ensure safety and maintain its chemical integrity.