In the end-functional PDMS modifier spectrum, the "phenolic OH spaced by three methylenes (–CH₂CH₂CH₂–) from Si-chain" and "linear PDMS mid-length (viscosity 60-120mm²/s)" jointly dictate phenoxide reactivity in interfacial phosgenation/transesterification with BPA, microphase domain size of PDMS in PC continuous phase, and final Si-PC copolymer low-temp impact (-30℃ notched >+40%) and HDT (+15-20℃) boundary. Plain HO-PDMS is incompatible with PC, only blends and bleeds; allylphenol-PDMS is reactive but residual allyl phenol hard to remove and yellows; pure silicone oil toughens but kills clarity. As silicon-modified polycarbonate (Si-PC) in thin-wall electronic shells, headlamp covers, 5G radomes demands "end-phenol copolymerizable, RI 1.42-1.43 matching PC (1.586 tunable), vol ≤1%, Pt-Co ≤100, 25℃ visc 60-120mm²/s, 24mo sealed RT," sourcing a light-red-brown transparent, density 0.980-0.990g/cm³, 158167-48-7, 25L/200L/1000L IBC product has become the core gap for domestic Si-PC comonomer localization.
Addressing this "phenol-propyl end" pain point,
Anhui IOTA Silicone Oil Co., Ltd. (IOTA) officially launches
Phenol-Terminated Silicone Oil IOTA 28723 (α,ω-Bis(propylphenol)polydimethylsiloxane, sibling 28724/28725/28729 higher-visc tiers). Characterized by "colorless-light-red-brown transparent oil, CAS 158167-48-7, 25℃ visc 60-120mm²/s, density 0.980-0.990g/cm³, RI 1.420-1.430, vol ≤1.0%, Pt-Co ≤100 (sibling ≤50), phenol end spaced by –CH₂CH₂CH₂–, 25L lined drum/200L iron/1000L IBC, sealed RT 24mo," and backed by "end-phenoxide copoly with BPA + PDMS flexible microphase toughening + propyl spacer anti-yellow," it serves as the "end-phenol anchor" for Si-PC copolymer, PC/ABS alloy, polyester/PU co-modification.
Molecular Architecture: End-Phenoxide Copoly + PDMS Flexible Microphase + Propyl Spacer Stable-Color 3D Logic
The core competitiveness of IOTA 28723 stems from its "HO–C₆H₄–CH₂CH₂CH₂–(Si(CH₃)₂O)ₙ–CH₂CH₂CH₂–C₆H₄–OH" propyl-phenol end architecture:
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End-Phenoxide Copoly: Both ends phenolic OH form phenoxide (–O⁻Na⁺) in NaOH/KOH solution, entering carbonate bond formation with BPA phenoxide + phosgene (COCl₂) or diphenyl carbonate in interfacial/melt process—silicone becomes copolymer segment, not physical disperse, killing bleed-out.
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PDMS Flexible Microphase： Mid n corresponds to 60-120mm²/s (Mn ~3000-6000), Si segment Tg≈-120℃, introduces 5-50nm microphase domains in PC; silver-tip stress relaxed by silicone segment, low-temp (-30℃) notched impact +40%+, siloxane raises LOI toward UL94 V-0.
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Propyl Spacer Stable Color： –CH₂CH₂CH₂– between phenol ring and Si atom isolates phenol ring from Si–H residue/Pt oxidative coupling; Pt-Co ≤100 (sibling high-grade ≤50), 2mm PC sheet Δb*<1.0; vs eugenol-end PDMS, no ene-bond residue means no double-bond oxidation yellowing in thermal aging.
Performance Leap: From "HO-PDMS Blend Bleed" to "End-Phenol Copoly Si-PC Tough-Heat"
Incorporating IOTA 28723 enables qualitative leaps:
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Si-PC Copolymer (Interfacial Phosgene): 3-15wt% vs PC, copolymerize with BPA phenoxide—Si-PC film 1.5m drop no crack, HDT 135→150-155℃, 2mm transmittance >88%, for laptop shell/phone back.
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PC/ABS Alloy Toughen： Inject 28723 (1-5%) at twin-screw melt stage, end-phenol reacts with ABS residual OH/PC chain-end, alloy -40℃ impact +30%, better paint adhesion.
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Polyester (PBT/PET) Co-mod： End-phenol reacts with PET chain-end carboxyl/OH, lifts PBT notched impact and arc resistance, for connectors.
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PU/Lube/Release： End-phenol caps PU prepolymer NCO for soft non-tack TPU; or high-temp chain oil (vol ≤1% at 250℃), PC injection release (no mold stain).
Application Penetration: From Laptop Shell to Headlamp
IOTA 28723 covers sectors triply sensitive to "end-phenol copoly + transparent tough + heat no-yellow":
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Electronics： Thin-wall laptop/tablet shell, 5G radome, EV charger transparent window.
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Automotive： Headlamp cover (PC transmit + stone-impact), halogen-free interior, HUD transparent part.
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Engineering Plastic： Si-PC copolymer, PC/ABS, PC/PBT alloy, transparent FR modifier.
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Additive Extend： High-temp lube oil, release agent, polyester/PU copoly monomer.
IOTA Technical Guide: Phenoxide Then Copoly, Sealed 24Mo
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Copoly Feed： Interfacial phosgene—dissolve 28723 in CH₂Cl₂/NaOH aq to phenoxide org phase, with BPA phenoxide + COCl₂ continuous, pH 11-12.5; transesterification—28723 with diphenyl carbonate + BPA under Ti(OBu)₄, melt polycondense, 3-15wt% silicone.
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Blend Modify： Twin-screw main PC pellets + liquid 28723 side-feed (1-5%), 230-260℃ shear, end-phenol grafts PC chain-end, no late bleed.
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Visc Select： 28723 (60-120cst) for thin-wall high-flow Si-PC; thick/high-silicone pick 28725 (100-160) or 28729 (190-230); 28724 (70-130) middle.
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Taboo Red Line： Phenol OH metal-ion sensitive—avoid long Fe³⁺/Cu²⁺ contact (Pt-Co rises); before copoly dewater (siloxane may cleave under strong base high-temp long boil, control NaOH <20%); no direct co-heat with peroxide curative (phenol promotes decomposition); strict-clear parts pick sibling ≤50Pt-Co.
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Storage： 25L/200L lined iron or 1000L IBC (25/200/1000kg); sealed RT; shelf 24 months, retest visc/color/phenol-value and extend if qualified; non-haz general chemical, gloves/goggles (phenol mild irritant).
Industry experts note that under electronics "thin-wall + drop-proof + clear", headlamp "transparent + halogen-free FR", and domestic Si-PC replacing Sabic EXL series, propylphenol-end PDMS is upgrading from "Momentive/Kaneka/Mitsubishi import followers" to "Si-PC copoly reference monomer." IOTA 28723, with its "CAS 158167-48-7 + 60-120cst + RI 1.42-1.43 + vol ≤1% + Pt-Co ≤100 + 24mo" hard metrics,
fills the domestic supply chain gap for phenol-terminated modified silicone oil in Si-PC copoly/PC-alloy toughening, providing a mass-producible path to replace imported end-phenol silicones (e.g., Momentive TSF phenol-end grades) for downstream modifier and PC-resin plants. This confirms domestic functional silicones are advancing steadily along "HO-PDMS (incompatible) → allylphenol-PDMS (yellow) → propylphenol-PDMS (stable-color copoly)," with growing technical say in silicon-modified engineering-plastic key monomers.
