In molecular architecture for addition-cure silicones and thermal interface materials (TIM), the "topology" and "number of vinyl end-groups" of polysiloxane jointly dictate crosslink network uniformity, low-shear viscosity, and flow behavior under high filler loading. Linear bis-vinyl PDMS gives isotropic network but shear-thickens badly at high filler; branched multi-vinyl resins cut viscosity yet risk local over-crosslink gel. As high-thermal greases, conductive gels, and LSR demand "multi-vinyl addable + Q-cage viscosity-cut + modulus tunable + flow superior," sourcing a four-arm vinyl-terminated Q-type PDMS with Mn 4000-12000, PDI<1.80, visc 20-50mPa·s has become the core gap for domestic multi-arm silicone modifier localization.
Addressing this "Q-core four-arm" pain point,
Anhui IOTA Silicone Oil Co., Ltd. (IOTA) officially launches
Vinyl-Terminated Q-Type Polydimethylsiloxane IOTA 22714. Characterized by "colorless to light yellow transparent liquid, Mn 4000-12000 Da, PDI<1.80, visc 20-50mPa·s (25℃), free Cl⁻ <50ppm, 1/5/25/200kg N₂-flushed lined drums, 3-month shelf (re-inspect extend)," and backed by "four-arm simultaneous hydrosilylation + SiO₄/₂ Q-cage viscosity-cut + narrow multi-arm topology," it serves as the "Q-core anchor" for addition-cure modulus tuning, TIM flow improvement, and multi-arm silicone network building.
Molecular Architecture: Q-Cage + Four-Arm Vinyl Star Logic
The core competitiveness of IOTA 22714 stems from its star asymmetric structure "Q unit (SiO₄/₂) core, four PDMS arms end-capped with vinyl":
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Q-Cage Rigid Viscosity-Cut: Center is silicone Q node (Si bridged by 4 oxygens); versus pure linear PDMS, Q-core gives spatial hindrance and radial chain geometry, lowering entanglement probability under shear—same Mn viscosity (20-50cSt) far below linear bis-vinyl (~80-150cSt at equal Mn); Q-core also thermo-oxidatively stabler than T/M units.
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Four-Arm Syn-Addition: All four PDMS arm ends bear –Si(CH₃)₂CH=CH₂, hydrosilylate with Si–H under Pt giving 4 crosslink anchors per molecule (equiv tetrafunctional), but each arm length controllable (total Mn 4000-12000, single arm 1000-3000), network node spacing uniform—avoids linear "long-chain bridging" excessive rebound, and branched resin "short-arm dense-net" brittle.
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Narrow Multi-Arm Controllable: PDI<1.80 is fairly narrow for star polysiloxane, ensures four-arm length uniformity, predictable modulus after cure; free Cl⁻ <50ppm meets electronic TIM cleanliness.
Performance Leap: From "Linear Bridging" to "Q-Core Even-Net"
Incorporating IOTA 22714 enables qualitative leaps:
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TIM Flow Jump: In Al₂O₃/AlN high-load (80-85wt%) conductive gel, replacing part linear vinyl oil cuts extrusion viscosity 30-50%, no stringing, no collapse after reflow, thermal conductivity not sacrificed (3.0→3.2W/m·K) due to even net.
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Addition Silicone Mid-Modulus: With bis-vinyl + H-silicone, four-arm gives "soft-not-collapse" elasticity at medium crosslink density, Shore A 20-40 easily tuned, elongation 800-1200% superior to pure bis-vinyl.
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Thermal Pad Creep Resist: In molded thermal pads 5-15% addition, Q-core restricts high-temp creep, 150℃×72h compression set from 35% down to 18%.
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LSR Rheology Opt: In LSR injection, lowers high-shear viscosity, shortens fill time, reduces flash.
Application Penetration: From Conductive Gel to LSR Molding
IOTA 22714 covers sectors doubly sensitive to "multi-arm crosslink + viscosity-cut flow":
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Thermal Interface: Thermal grease, conductive gel, phase-change pad, automotive power module TIM.
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Addition Silicone: Liquid silicone rubber (LSR), silicone keys, medical tubing, low-modulus gaskets.
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Electronic Potting: High-fill flame-retardant encapsulant, LED module package.
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Specialty Elastomer: Aerospace cable insulation, high-low temp seals.
IOTA Technical Guide: Pt-System Detox, Four-Arm Metering
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Addition Formula: Blend with bis-vinyl PDMS, end/side H-silicone; count IOTA 22714 vinyl as 5-25% of total vinyl mol, but ×4 per molecule for total Vi mol; Si–H:total Vi = 1:1.0-1.3, Pt 5-50ppm.
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TIM Compounding: Homogenize with base vinyl oil first, then add filler (three-roll/planetary); Q viscosity-cut amplifies after filler addition; if using silazane-treated filler, synergistic.
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Taboo Red Line: No strong acid/base, amines, thiols, organotin Pt poisons; N₂-seal against vinyl-end oxidative self-poly; free Cl⁻ <50ppm controlled, no chloroplasticizers.
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Storage: 1/5/25/200kg N₂-flushed lined drums, reactive multi-arm silicone; cool dry sealed, 3 months shelf, overdue re-inspect visc/vinyl and use if qualified; unfinished N₂-reseal <25℃ light-proof.
Industry experts note that under dual pull of compute-chip high-thermal TIM and LSR precision molding, multi-arm Q-type vinyl silicones are shifting from "topology lab curiosity" to "flow-modulus dual-tuner mainstream aid." IOTA 22714, with its "four-arm vinyl + Q-cage + 20-50cSt" hard metrics,
fills the domestic supply chain gap for Q-type multi-arm vinyl PDMS in TIM flow improvement and addition-cure mid-modulus tuning, providing a mass-producible path to replace imported Shin-Etsu four-arm Vi Q silicone, Momentive MQ multi-vinyl resin for downstream rubber plants. This confirms domestic functional silicones are advancing steadily along "topology multi-arm → Q/M/T core tunable → vinyl-end-count designable," with growing technical say in silicone network-architecture auxiliaries.
