A Hydrogen-Containing Di-Phenyl Siloxane Cross-Linker for Ultra-High Hardness and High Refractive Index Silicone Rubber and its application in LED encapsulation

doi:10.21203/rs.3.rs-2098890/v1

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Research Article

A Hydrogen-Containing Di-Phenyl Siloxane Cross-Linker for Ultra-High Hardness and High Refractive Index Silicone Rubber and its application in LED encapsulation

https://doi.org/10.21203/rs.3.rs-2098890/v1

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published 16 Jan, 2023

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Herein, a linear hydrogen cross-linker with a high hydrogen content was proposed in the study. The hydrogen-containing di-phenyl silicone oil (HDPSO) was fabricated by non-hydrolytic sol-gel reaction and ring-opening polymerization. After raw materials were mixed with vinyl base polymer, the cured sample showed ultra-high hardness (~ 92 shore D), refractive index (~ 1.542 at 633 nm), and transparency (~ 92.6% at 450 nm). After lighting for 168 h at room temperature, the samples showed no yellowing phenomenon and the lumen depreciation was only 4.9%. The samples demonstrated outstanding reliability compared to other commercialized silicone materials. The HDPSO is a promising cross-linker candidate for reliable high-performance LED encapsulantion.

As a solid-state semiconductor light-emitting device, LED is gradually replacing traditional light-emitting devices in various application scenarios. LED of high power, high energy efficiency, high brightness, and high reliability also requires LED packaging materials with the better optical properties, mechanical properties, and weather resistance.

The hardness of silicone materials in LED encapsulation is merely 50 ~ 70 shore A (about 30 ~ 40 shore D). And there is no silicone materials for LED packaging have been reported with a hardness over 80 Shore D until now^[1–4]. The higher hardness of the material can protect LED device from damage caused by external impact more effectively. The refractive index of LED packaging materials largely determines the light extraction efficiency of LED. The refractive index of common packaging materials is generally between 1.4 and 1.5 and much lower than that of general GaN light-emitting chips (RI ≈ 2.45)^{[5, 6]}. The difference in the refractive index between LED chip and packaging materials results in total reflection at the interface, which leads to light loss and reduced luminous efficiency of the device^{[7, 8]}.

The introduction of inorganic nanoparticles with a high refractive index is the most direct method to prepare materials with a high refractive index and high hardness^{[9, 10]}. However, the nanoparticles gradually agglomerate, thus significantly affecting the light transmittance of the materials, so the materials can‘t be preserved for a long time. In addition, the added filler also increases the viscosity of the curing system sharply and decreases the fluidity, thus affecting subsequent processing steps.

The properties of addition-curing silicone materials can be adjusted by changing the molecular structures of two polysiloxanes. Due to the high ratio of dielectric polarizability to molar volume, phenyl groups are usually introduced to improve the refractive index of a silicone material used in LED packaging^[11–14]. At the same time, as a rigid group, the content of phenyl will also affect the hardness of the material.

Fan et al.^[15] synthesized a hydrogen-containing cross-linker with dihydroxydiphenylsilane and MM^H with the catalyst of HCl. After curing with vinyl basic polymer, a silicone material with light transmittance of 86.6% (at 450 nm), a refractive index of 1.581 (at 589 nm), and hardness of 48 shore D was obtained. However, the preparation of the material involves relatively harsh conditions (140℃ under vacuum condition) and the complex synthesis route, which largely restrict its application scope.

Yang et al. ^[16] synthesized a hydrogen-containing cross-linker with a high refractive index (~ 1.53 at 589 nm) and high transmittance with Karstedt’s catalyst. After it was cured with vinyl base polymer, a silicone material with 92 shore A and tensile strength of 3.8 MPa was obtained, but its transmittance was too low and negatively affected the light extraction efficiency of the prepared LED.

Bae et al.^[17] synthesized a linear hydrogen-containing cross-linker through non-hydrolytic sol–gel condensation. After it was cured with vinyl silicone resin, a high-performance LED encapsulant with high transmittance (~ 89.2% at 450 nm) and a refractive index (1.579 at 633 nm) was obtained. However, methyl diethoxysilane used in the synthesis was expensive.

Commercially available hydrogen-containing cross-linkers have a high hydrogen content of about 0.38wt% and a refractive index of about 1.50. Hydrogen-containing cross-linkers with a higher refractive index, a higher hydrogen content, and excellent comprehensive properties were seldom reported.

In previous work^[18], we reported a hydrogen-containing methyl-phenyl silicone resin with a high refractive index (~ 1.48 at 633 nm). When it was mixed with vinyl base polymer for curing, the crosslinking density of the products was greatly improved and the hardness reached 86 shore D. However, because of the difference in the curing rate in polymer networks, the curing rate of products inevitably showed the non-uniform crosslinking phenomenon^[19]. Due to the network structure formed by the T-link of phenyltrimethoxysilane and a high phenyl content, the stiffness of the products was further increased and a large internal stress was generated in the curing process. These reduce the tensile strength of the product and make it easy to break during the curing process

In this study, in order to replace reticulated silicone resin, we redesigned and synthesized a new linear hydrogen cross-linker to solve the aforementioned problems related to encapsulation. The synthesis process generated no waste water and was simple. First, a linear hydroxy-terminated di-phenyl silicone oil (HTDPSO) was formed by non-hydrolytic sol–gel condensation between diphenyl silanediol and diphenyldimethoxysilane. Then, the obtained hydroxy-terminated phenyl silicone oil reacted with tetramethylcyclotetrasiloxane to form a long-chain linear hydrogen-containing cross-linker, which could realize high condensation and reduce the internal stress during curing. In addition, the process retained the advantage of the hydrogen-containing silicone oil: controllable hydrogen content. After curing, the product showed good optical properties, high reliability, greatly improved tensile strength, and high hardness of 92 shore D, which was much higher than that of reported LED packaging materials.

2.1. Materials

Diphenyl silanediol (DPSD) and diphenyldimethoxysilane (DPDMS) were supplied by Shenzhen Superior Changhao Technology Co., Ltd., China. 2, 4, 6, 8-tetramethylcyclotetrasiloxane (D₄^H) was purchased from Hangzhou Jianbang Technology Co., Ltd., China. Vinyl-phenyl MT silicone resin (VPMT) and adhesion promoter G-02 were purchased from Guangdong Jieguo New Material Co., Ltd., Guangdong, China. 1, 1, 3, 3-tetramethyldisiloxane (MM^H), acidic cation-exchange resin CH-01, and chloroplatinic acid were provided by Guangdong Kejunchi Technology Co., Ltd., China. Basic anion exchange resin D296R was obtained from Tianjin Nanda Resin Co., Ltd., China. KE8081 as an inhibitor was purchased from Guangzhou Kanggujia Synthetic Material Co., Ltd., Guangdong, China. 9851 was supplied by Guangdong Jieguo New Material Co., Ltd., Guangdong, China.

2.2. Synthesis of Hydroxy-terminated Di-phenyl Silicone Oil

DPDMS and DPSD (1:1 molar ratio) were loaded into a four-necked flask equipped with a condenser, a magnetic stirrer, and thermometers. When DPSD was completely dissolved, the temperature rose to 95℃. Then the basic anion exchange resin D296R ( 2 parts per hundreds of siloxane) was dropped into reactants. Subsequently, the reaction proceeded respectively at 95℃ for 2 h, 125℃ for 2 h, and 140℃ for 2 h. Then, the mixtures were filtered to remove D296R under reduced pressure. Finally, through vacuum distillation, small molecules were removed from the organic layer and viscous, colorless, and transparent HTDPSO was obtained. The synthesis process is shown in the first step in Fig. 1.

2.3. Synthesis of Hydrogen-containing Di-phenyl Silicone Oil

HTDPSO, D₄^H, and MM^H (15:9:1 mass ratio) were used to prepare HDPSO. The reaction proceeded at 55°C for 2 h and 60°C for 6 h under the catalytic action of cation exchange resin CH-01 (1 parts per hundreds of siloxane). After that, the products were filtered to move CH-01 under reduced pressure. Then, through vacuum distillation, small-molecule byproducts were removed. Finally, colorless and transparent hydrogen-containing phenyl silicone oil with moderate viscosity was obtained. The synthesis process is shown in the second step in Fig. 1.

2.4. Curing of phenyl Silicone Products

The phenyl silicone materials were cured through the hydrosilylation reaction between VPMT and HDPSO. VPMT was mixed with HDPSO at different Si-H/Si-Vi molar ratios. In addition, G-02 (1 phr), KE-8081 (1 phr), and chloroplatinic (10 ppm) were respectively added as adhesion promoter, inhibitor, and catalyst. The catalyst firstly coordinated with hydrosilane to form intermediate complexes and then attacked the intermediate complexes via vinyl group to obtain addition products^[20]. Then, the mixtures were degassed in vacuum and poured into a cup-like LED bracket or dumbbell mold. The addition reaction was performed at 90°C for 1 h and then 150°C for 2 h. Finally, the corresponding products used as LED encapsulants were labeled as Sample-1, Sample-2, and Sample-3, respectively. 9851 as a comparison sample, was thermally cured under the same conditions.

2.5. Measurements

Fourier-transform infrared (FT-IR) spectrometer (Bruker, NICOLET ANTARIS) and ¹H nuclear magnetic resonance (¹H-NMR) spectrometer (Bruker, AVANCE III400) were used to detect functional groups and structures of samples. Gel permeation chromatography (GPC) was performed on Agilent Instrument 1260 to determine the molecular weight and distribution of oligosiloxane resins. The viscosity of silicone resins was tested by a viscometer (Shanghai Hengping Instrument and Meter Factory, NDJ-5S) at 25°C. Abbe refractometer (Shanghai CSOIF Co., Ltd., 2WA-J) was used to measure the refractive index of samples at 25°C. A shore durometer (Shanghai Yuanling Instrument Co., Ltd., LX-D) was used to test the hardness of cured silicone materials according to GB/TB531-1999. The light transmittance of cured products were recorded using a UV-Vis spectrophotometer (Hitachi, U3900). The thermal aging test was conducted in a forced convection oven at 200°C for 24 h. A thermal-gravimetric analyzer (TA, TGA550) was used to determine the weight loss of samples in the range of 40°C to 700°C under nitrogen protection. Differential scanning calorimetry (DSC) was performed on a TA instrument DSC250 with a heating rate of 10°C min^− 1 under a N₂ atmosphere. The tensile strength was measured with an electronic universal tester (Instron, I1) according to GB/TB528-2009. LEDs encapsulated by packaging materials was lit for 168 h at a current of 50 mA for a lumen depreciation test. The luminous fluxes of encapsulated LEDs before and after illumination were measured with a high-accuracy array spectroradiometer (Hangzhou Hopoo Co., Ltd.). Reflow soldering (265°C ± 5°C) was carried out for five cycles to evaluate the thermal resistance of the encapsulants in LED lead frames.

3.1. Hydrogen-containing Di-phenyl Silicone Oil

3.1.1. Characterization of Hydroxy-terminated Di-phenyl Silicone Oil and Hydrogen-containing Di-phenyl Silicone Oil

Figure 2 shows the Fourier-transform infrared (FT-IR) spectra of HTDPSO and HDPSO. HTDPSO is the precursor of HDPSO, so some absorption bands in their FT-IR spectra were the same. HTDPSO has the main chain of Si-O-Si bond, side chains of phenyls, and terminals of hydroxyls. All raw materials had difunctional groups, so the main chain presented a linear structure. The broad shoulder peaks in the wavenumber range from 1000 cm^− 1 to 1200 cm^− 1 could be attributed to siloxane bonds (Si-O-Si) generated in the condensation reaction. In addition, the four peaks in the wavenumber range from 2940 cm^− 1 to 3140 cm^− 1 were attributed to the stretching vibrations of phenyl groups (–Ph). The peak at 1430 cm^− 1 was the skeleton vibration peak of –Ph.

HDPSO was synthesized through the ring-opening reaction of D₄^H and grafting reaction with terminal hydroxyls in HTDPSO. So, some characteristic peaks of HTDPSO and HDPSO were different. HTDPSO had a strong characteristic peak of silanol groups (Si-OH) at 3410 cm^− 1, which was not observed in the spectrum of HDPSO, indicating that after the second step of the reaction, the -OH of HTDPSO was eliminated.

The characteristic peaks at 1260 cm^− 1 and 2910 cm^− 1 in the spectrum of HDPSO were assigned to the symmetric deformation vibration and stretching vibration of methyl groups (-CH₃), respectively. Similarly, the peaks of methyl groups (–CH₃) of HDPSO were clearly observed, whereas the peaks were not observed in the spectra of HTDPSO. These results confirmed that D₄^H and MM^H were grafted into silicone oil. HDPSO showed a single spike at 2165 cm^− 1 (Fig. 2), but the spike was not observed in the spectrum of HTDPSO, further revealing the successful grafting of D₄^H and MM^H.

The structures of HTDPSO and HPSR were analyzed based on ¹H nuclear magnetic resonance (¹H-NMR) spectra (Fig. 3). Similar to their analysis results of FT-IR spectra, they exhibited some of the same chemical shifts. The signals of solvent chloroform-D were determined at 7.26 ppm. The peaks in the range from 7.08 ppm to 7.44 ppm were assigned to protons of phenyl groups. The chemical shifts of methyl (Si-CH₃) groups were observed in the range from − 0.12 ppm to 0.21 ppm. The methyl (Si-CH₃) peaks was observed in the spectrum of HDPSO, but they were not observed in the spectrum of HTDPSO, indicating that HTDPSO reacted with D₄^H. In addition, HTDPSO had the proton signals of silanol (Si-OH) at 3.25 ppm to 3.62 ppm, which were absent in the spectrum of HDPSO. HDPSO had the strong and sharp bands of silicon hydrogen bond (Si-H) at 3.26 ppm, which were not observed in the spectrum of HTDPSO. The differences proved that the residual hydroxyl (–OH) groups were reduced via the reaction, to form highly condensed oligosiloxane with a linear structure.

According to the¹H-NMR spectra, the molecular weight of HTDPSO and HDPSO were calculated. In HTDPSO, the ratio of silanol to phenyl is approximately 1:4, and its molecular weight is calculated as 414. In HDPSO, the ratio of silicon hydrogen bond to phenyl and methyl is approximately 2:2:3, and the molecular weight was calculated as 650.

The analysis of Fourier-transform infrared (FT-IR) and ¹H nuclear magnetic resonance (¹H-NMR) spectra demonstrated that HDPSO was successfully synthesized after two condensation reactions.

3.1.2. Properties of Hydroxy-terminated Phenyl Silicone Oil and Hydrogen-containing Di-phenyl Silicone Oil

Table 1

Properties of Hydroxy-terminated Phenyl Silicone Oil (HTDPSO) and Hydrogen-containing Di-phenyl Silicone Oil
Prepolymers	H(wt%)	M_n ^a	M_w ^b	Đ ^c	RI	Viscosity (mPa·s)
HTDPSO	-	383	463	1.2095	1.591	1678
HDPSO	0.62	697	1193	1.7159	1.528	873
^a M_n: Number-average molecular weight. ^b M_w: Weight-average molecular weight. ^c Đ: Polydispersity index

Table 1 lists various properties of HTDPSO and HDPSO. Due to the low reactivity of non-hydrolytic sol-gel method, the molecular weight of HTDPSO is relatively small, but the emergence of gel is also avoided. As shown in Fig. 1, HTDPSO has a linear structure with a short molecular chain. This structure gives it more active groups, hydroxyl, which reacts with D₄^H to form a long chain of linear silicone oil (HDPSO). At the same time, the molecular weight of HDPSO increased after the introduction of D₄^H, but the refractive index decreased with the decrease in phenyl content. The introduction of D₄^H also reduced the steric hindrance of molecules, so that the viscosity of HDPSO with increased molecular weight was lower than that of HTDPSO. The popydispersity index (PDI) of HTDPSO and HDPSO reached 1.7, revealing that they were homogenous products.

The M_n of HTDPSO measured by GPC was 383, which was close to 414 that calculated by ¹H-NMR spectra. And the M_n of HDPSO measured by GPC was 697, which was close to the value that calculated by ¹H-NMR spectra, too. All the molecular weight calculated by ¹H-NMR were provided reliability of GPC method.

3.2. Cured phenyl Silicone Products

3.2.1. Effects of Different Si-H/Si-Vi Ratios on Cured phenyl Silicone Products

Table 2

Properties of phenyl Silicone Products
Cured Products	Si-H/Si-Vi	RI	hardness of cured product(shore D)	Transmittance at 450 nm	Appearance of cured products
9851	-	1.545	50	89.5	transparent and smooth
Sample-1	1:1.4	1.542	91	92.6	transparent and smooth
Sample-2	1.4:1	1.532	92	89.2	transparent and smooth
Sample-3	1:1	1.536	91	89.8	transparent and cracking
^a The specific measurement methods were shown in supporting information.

Various properties of the phenyl silicone products are listed in Table 2. The hardness of three samples were all above 90D, which was much higher than that of the commercial silicone 9851. With the increase in the proportion of linear silicone oil, the RI of the products decreased gradually due to the low RI of HDPSO. However, the hardness of the products changed little with the increase in the proportion. The results might be interpreted as follows. A large number of benzene rings greatly improved the stiffness of the products and the effect of crosslinking density on the hardness was small. Moreover, Sample-3 confirmed that high crosslinking density affected the formation of the homogeneous structure, thus resulting in cracks in the curing process of the product.

3.2.2. Optical Performance of Di-phenyl Silicone Products

Transmittance is the most important optical property of LED packaging materials and greatly affects the light extraction efficiency. Figure 4 shows the transmittance of four products in the range of 400 to 800 nm. Due to the high hydrogen content and high RI of HDPSO, all the three prepared products showed the transmittance above 89% at 450 nm. The transmittance of Sample-1 reached 92.6%, which was much higher than that of 9851. The difference might be interpreted as follows. HDPSO has a linear structure and VPMT has a ternary ring spherical structure as the center. HDPSO and VPMT had good compatibility. The high hydrogen content of HDPSO provided high reaction activity. However, there was still a certain gap between the RI of HDPSO and VPMT. Therefore, the higher proportion of HDPSO had the more significant influence on transmittance of products. Since Sample-3 cracked during curing and did not show outstanding transmittance, it was not tested in subsequent experiments.

3.2.3. Thermal Stability of Di-phenyl Silicone Products

The LED chips generated a lot of heat under working conditions, thus forming high-temperature environment. Therefore, an encapsulant with a good thermal stability was required. 9851 showed the obvious yellowing phenomenon after thermal aging at 200℃ for 24 h (Fig. 5), whereas the phenomenon was not observed in Sample-1 or Sample-2 even after long-term thermal aging. After thermal aging, the transmittance of 9851 was decreased by 8.2% and the transmittance data of Sample-1 and Sample-2 were decreased by 5.9% and 6.2%, respectively. The results proved that HDPSO improved the crosslinking density and thermal stability of the products, as confirmed in Fig. 6.

To evaluate the thermal stability of 9851, Sample-1, and Sample-2, thermogravimetric analysis (TGA) was conducted (Fig. 6). In N₂ atmosphere, the products experienced three stages in the thermal stability test. In the first stage, the weight loss was small and mainly ascribed to the loss of water and other small molecules. In the second stage, due to the decomposition of organic functional groups such as phenyl groups, the weight of silicone materials declined quickly. Finally, the weight loss rate gradually decreased because of the breaking of Si–O-Si at high temperatures. The temperatures corresponding to of 5% weight loss of Sample-1 and Sample-2 were respectively 484.4℃ and 466.1℃, whereas that of the 9851 commercial silicone resin was 446.8℃. It proved that the products cured by HDPSO cross-linker have excellent thermal stability. In addition, the temperature at which Sample-2 began to lose weight was significantly lower than that of Sample-1. HDPSO had a linear structure and lower steric hindrance and more easily lost organic groups at high temperatures. However, VPMT contained more methyl, which was easier to decompose at high temperatures than phenyl. Therefore, Sample-1 lost more weight in the second stage.

3.2.4. DSC characterization of Di-phenyl Silicone Products

As for silicone LED encapsulant, if its glass transition temperature (T_g) was too low, the strength of the product could not protect the device at room temperature. If T_g was too high, the internal stress of the product would increase, thus increasing the possibility of device failure. We believed that the T_g of the product should be slightly higher than the room temperature, so that the encapsulant could fully protect the device from damage when the device was in standby mode. When the device was in working mode, it would not be damaged under the increasing internal stress. As a rigid group, the content of phenyl can increase the Tg of the silicone.

Through DSC test, we obtained the T_g of the three products (Fig. 7). 9851 had the lowest T_g (18.6℃) and showed a highly elastic state at room temperature. In this form, the strength of the product could be reduced. The T_g of Sample-1 and Sample-2 respectively reached 45.4℃ and 29.8℃, which was higher than that of 9851. The difference might be interpreted as follows. With the increase in crosslinking density, the free volume decreased and the chain was blocked, so the T_g of the product decreased. Sample-2 contained more HDPSO with linear structures, so its molecular chain was more flexible and its Tg was lower than that of Sample-1.

3.2.5. Mechanical properties of Di-phenyl Silicone Products

We evaluated the toughness of products in terms of the elongation at break and tensile strength. With the increase in elongation at break, the tensile strength of the product gradually increased and then peaked and the product was completely broken (Fig. 8). The maximum tensile strength of 9851 commercial silicone resin, Sample-1, and Sample-2 respectively reached 6.98 MPa, 8.86 MPa, and 7.02 MPa. The elongation at break of 9851 commercial silicone resin, Sample-1, and Sample-2 respectively reached 27.6%, 9.5%, and 14.6%. The results proved that the elongation at break of the product decreased with the increase in tensile strength. In the test environment, Sample-1 was in glass state (Fig. 7), so the product had higher strength. 9851 was in high elastic state, so the product had the higher elongation at break. Meanwhile, Sample-2 was between the high elastic state and the glass state under test conditions, so neither the tensile strength nor the elongation at break had a good performance.

3.2.6. Reliability of Di-phenyl Silicone Products

In the long-term operation of LED devices, silicone encapsulant gradually ages under the action of external environment, thus reducing the light extraction efficiency and lifetime of the devices. To estimate the reliability of products, two samples with different mixing ratios and 9851 were used to encapsulate LEDs. The packaged LED devices were subjected to illumination for 168 h at room temperature. The working current was set to be 50 mA to simulate working conditions. Among the three products, Sample-1 had the best photoelectric performance and has the least impact on the luminous efficiency of LED chip (Fig. 9). After lighting for 168 hours, the performance of the blank sample without encapsulation deteriorated greatly, while that of the encapsulated samples declined little. Therefore, it could be concluded that encapsulants could protect the LED devices.

The lumen depreciation of LEDs without packaging materials reached 47.7%, while that of LEDs packaged with 9851 was 20.9%. The lumen depreciation of Sample-1 and Sample-2 respectively decreased to 4.9% and 8.6%, displaying its strong reliability.

Actually, LED devices would be reflowed at the maximum temperature of 270℃, which poses a great challenge to the reliability of packaging materials. A reflow soldering test (265°C ± 5°C) was carried out to simulate the actual industrial production. After five cycles, the products were still colorless and transparent, proving their reliability.

In the study, we successfully prepared a non-hydrolytic sol-gel derived linear hydrogen cross-linker with a high hydrogen content. After it was mixed with vinyl base polymer, the cured sample showed substantial thermal stability against discoloration. It also had ultra-high hardness (~ 92 shoreD) and strength to protect the LED from thermal stress and external forces during operation. The high refractive index (~ 1.535 at 633 nm) and transmittance (~ 92.6% at 450 nm) ensured its good light extraction efficiency. After working for 168 h at room temperature, it showed tiny lumen depreciation (4.9%). Its reliability supported the long lifetime and greatly exceeded that of commercial phenyl polysiloxane resins. The non-hydrolytic sol–gel derived HDPSO is a promising candidate cross-linker for reliable LED encapsulation.

Acknowledgements

This project was supported by Guangdong Basic and Applied Basic Research Foundation

Funding Statement

This work was supported by Guangdong Basic and Applied Basic Research Foundation under the grant No. 2021A1515010945, 2022A1515010365.

Author Contributions

Zhaoqun Pan contributed to conception of the study; Yu Cheng performed the experiment; Zhaoqun Pan, Yu Cheng contributed significantly to analysis and manuscript preparation; Zhaoqun Pan, Yu Cheng performed the data analyses and wrote the manuscript; Yu Cheng and Bohao Li helped perform the analysis with constructive discussions; Zhun Zhang helped performed the experiment.

Data Availability

All data generated or analyzed during this study are included in this published article.

Compliance with Ethical Standards

Conflict of Interest

The author declare that they have no conflict of interest.

Consent to Participate Not applicable.

Consent for Publication Not applicable

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published 16 Jan, 2023

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A Hydrogen-Containing Di-Phenyl Siloxane Cross-Linker for Ultra-High Hardness and High Refractive Index Silicone Rubber and its application in LED encapsulation

Status:

Journal Publication

Version 1

Abstract

Figures

1. Introduction

2. Experimental

2.1. Materials

2.2. Synthesis of Hydroxy-terminated Di-phenyl Silicone Oil

2.3. Synthesis of Hydrogen-containing Di-phenyl Silicone Oil

2.4. Curing of phenyl Silicone Products

2.5. Measurements

3. Results And Discussion

3.1. Hydrogen-containing Di-phenyl Silicone Oil

3.1.1. Characterization of Hydroxy-terminated Di-phenyl Silicone Oil and Hydrogen-containing Di-phenyl Silicone Oil

3.1.2. Properties of Hydroxy-terminated Phenyl Silicone Oil and Hydrogen-containing Di-phenyl Silicone Oil

3.2. Cured phenyl Silicone Products

3.2.1. Effects of Different Si-H/Si-Vi Ratios on Cured phenyl Silicone Products

3.2.2. Optical Performance of Di-phenyl Silicone Products

3.2.3. Thermal Stability of Di-phenyl Silicone Products

3.2.4. DSC characterization of Di-phenyl Silicone Products

3.2.5. Mechanical properties of Di-phenyl Silicone Products

3.2.6. Reliability of Di-phenyl Silicone Products

4. Conclusion

Declarations

Acknowledgements

Funding Statement

Author Contributions

Data Availability

Compliance with Ethical Standards

Conflict of Interest

Consent to Participate Not applicable.

Consent for Publication Not applicable

References

Additional Declarations

Status:

Journal Publication

Version 1