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Buy uv absorber, 4 problems as far as possible to avoid! 2024-03-02 14:58:21.761
As a kind of polymer material, aging is a common phenomenon. In the process of using polymer materials, due to the comprehensive effect of environmental factors such as heat, oxygen, water, light, microorganisms and chemical media, the chemical composition and structure of polymer materials will undergo a series of changes, and the physical properties will deteriorate accordingly, such as hardening, sticky, brittle, discoloration, loss of strength, etc, these changes and phenomena are called aging. General Precautions 1. Humidity Polyester, polyacetal, polyamide and polysaccharide polymers can be hydrolyzed in water under the catalysis of acid or alkali. In areas with serious air pollution and frequent acid rain, the use of such polymer materials will be restricted. If a waterproof film can be covered on the surface of such materials, the occurrence of hydrolysis aging can be reduced or even avoided. 2-Oxygen In the process of polymer processing, amine antioxidants, phenolic antioxidants, sulfur-containing organic compounds and phosphorus-containing compounds are added, which can react rapidly with peroxy radicals and terminate the chain reaction early. 3. Light aging During the processing of the material, if the light stabilizer is added, the aging degradation of the material can be avoided. Depending on the mechanism of action, such light stabilizers include light shielding agents, ultraviolet absorbers, quenchers, and radical scavengers. Since there are so many influencing factors and corresponding measures in the use of plastic polymer materials, if it is very inconvenient to use, too many ingredients and complex proportions, it is recommended to use composite anti-aging agents. General composite anti-aging agents will consider comprehensive issues such as anti-oxidation, anti-ultraviolet, light stability, and shielding. General manufacturers in solving the problem of plastic aging, most of the 4 kinds of phenomenon, which 4 kinds of phenomenon? 1, only buy expensive, don't buy the right Think expensive one must be good, in fact, any additives have advantages and disadvantages, there are advantages, there must be disadvantages. For example, UV absorbers have different optimal absorption bands, ranging from 270-430NM to different types of UV absorbers. For the UV resistance of plastic products in different bands, choosing the right UV is the best choice. 2, only recognize foreign goods, not domestic It is believed that only foreign goods can solve the problem. In fact, it is not. The quality of imported additives is stable and reliable. However, if only one additive is used, the functional defect of the additive itself will be shown, which solves some problems, but cannot solve all functional problems. Of course, if the full selection of foreign goods, the effect should be good, you can use the cost? Raw material procurement? Will encounter a lot of trouble. 3, only buy general, not special Different plastics, different polymers internal molecular structure is not the same, some good oxidation resistance, some light resistance, some rain resistance, then the demand for this series of anti-aging is certainly not the same, how can we use the same routine to solve different problems. 4, only recognize ultraviolet absorption, do not consider other synergy The ultraviolet absorber has a good performance on ultraviolet light, but its function is still single, and there are so many factors affecting aging, which is not something that an ultraviolet absorber can handle. This requires us to consider comprehensively, handle ultraviolet light, and at the same time handle the problems of oxygen, heat and hydrophobicity, which is the first choice. Thus, the composite plastic anti-aging agent arises at the historic moment, which can better solve the comprehensive problem of plastic aging.
How to prevent the external migration of UV absorbers? 2024-03-02 14:57:55.733
采用有机合成方法制备反应型紫外线吸收剂﹖-羟基-4-(3-甲基丙烯酸酯基-2-羟基丙氧基)二苯甲酮(BPMA)。利用制得的BPMA，以聚偏氟乙烯(PVDF)粉体为基材，进行预辐照接枝反应，制得PVDF-g-BPMA。预辐照实验中PVDF的辐照剂量为15 kGy，在流变仪中的熔融接枝反应温度为190℃，反应时间为6 min，转速为50 r/min。通过核磁共振氢谱、傅里叶变换红外光谱、差示扫描量热、广角X射线衍射以及紫外–可见光谱等对PVDF-g-BPMA进行结构表征与紫外线吸收性能测试。结果表明，BPMA成功接枝到IPVDF上，接枝率达7.04%。接枝后PVDF的结晶度降低，但晶型未发生改变。相比于未接枝的PVDF，PVDF-g-BPMA薄膜在280~340 nm波长内的紫外光透过率降至0.27%以下，表现出优异的紫外线吸收性能，同时与PVDF/BPMA复合膜相比，其经乙醇抽提48 h后的紫外线吸收性能没有明显变化，表明PVDF预辐照接枝BPMA有效防止了紫外线吸收剂在PVDF内的外迁移。 　　聚偏氟乙烯(PVDF)是一种广泛应用于汽车、能源、航空、电子、化学工业等领域的高分子材料，具有优异的加工性、抗疲劳性、耐候性、耐沾污性、耐化学品性以及优良的电学、光学性能。目前对于PVDF的改性有很多研究，但对于提高其紫外线吸收性能未见相关报道。高分子材料在户外使用时，易被阳光中的紫外线激发，发生一系列光化学反应，导致分子结构破坏且性能降低，最后失去使用价值。紫外线吸收剂能有效地防止或延缓这类现象的发生，延长材料的使用寿命。因此，提高PVDF的紫外线吸收性能具有重要的意义。对于PVDF的改性方法主要有溶液处理、接枝处理、共混处理、气体处理等。 　　二苯甲酮类紫外线吸收剂是一种应用广泛的光屏蔽剂，已有多个品种商品化。其作用机理主要是通过分子间氢键作用，分子受紫外线辐照时吸收能量，发生共振且氢键被破坏，然后将紫外光能转化为较低的振动能并释放。小分子紫外线吸收剂在应用中易受外界环境影响发生迁移。因此，需要将紫外线吸收剂接枝到聚合物中或制备高分子型紫外线吸收剂。相对于其它方法，采用预辐照接枝方法可在分子链上产生自由基，进一步引发反应型小分子紫外线吸收剂的接枝反应，反应后具有较高的接枝率;且其具有反应易操作、实验条件易控制、对环境污染小、可大规模生产等优点。同时，反应过程中不需要引发剂，可以得到除单体均聚物外较纯净的接枝聚合物，单体不直接辐照，能够减少单体均聚反应。笔者以文献和为参照，以2，4-二羟基二苯甲酮(UV-)、甲基丙烯酸缩水甘油酯(GMA)为原料制备可聚合型的二苯甲酮类紫外线吸收剂——2-羟基-4-(3-甲基丙烯酸酯基-2-羟基丙氧基）二苯甲酮(BPMA)。将60 Co-vy射线预辐照过的PVDF与BPMA在微量混合流变仪中进行熔融接枝反应制备PVDF-g-BPMA。这类研究目前尚未见有关文献报道。实验测试结果表明，PVDF接枝BPMA后具有优异的紫外线吸收性能，有利于增加PVDF作为防护层材料的应用。同时，论述了一种除制备大分子紫外线吸收剂以外也能有效防止紫外线吸收剂迁移的实验方法，这对于在其它材料上的应用有一定的指导意义。 　　PVDF:Solef 6010，Solvay特种聚合物有限公司;UV-O，GMA︰分析纯，阿拉丁试剂公司;氢氧化钠(NaOH)、无水硫酸镁(MgSO 4)、浓硫酸、无水乙醇、乙酸乙酯、甲苯:分析纯，北京化工厂;石油醚:分析纯，天津市富宇精细化工有限公司;二甲基乙酰胺(DMAc):分析纯，西陇化工股份有限公司;硅胶:200~300目，精制型，青岛海洋化工厂分厂。 　　2.主要仪器与设备 　　傅里叶变换红外光谱(FTIR)仪:Bruker Vertex70型，德国Bruker公司;热重(TG)分析仪:TGA7型，美国Perkin-Elmer公司;差示扫描量热(DSC)仪:STARe System型，瑞士Mettler Toledo公司;核磁共振波谱(NMR)仪:Bruker AV 400型，德国Bruker公司;广角X射线衍射(WAXD)仪:D8 Advance型，德国Bruker公司;紫外可见分光光度计:UV 3600型，日本岛津公司;离子色谱(IC)仪:ICS-1000型，美国Dionex公司;微量混合流变仪:Minilab CTW5型，德国Thermor Fisher公司。 　　3.BPMA的合成 　　参照文献和的方法，将UV-0(8.56 g,40 mmol)和GMA(6.24 g，44 mmol)同时放入250 mL三口圆底烧瓶中，通氮气保护，室温下磁子搅拌均匀后，加入NaOH(0.124 g，3.1 mmol)作催化剂，温度设置80C开始加热，通冷凝水搅拌反应7h后停止，得到黄色粘稠液体。温度降至室温后加入甲苯溶解，用配置的1%稀硫酸洗涤除去NaOH后加MgSO4搅拌20 h，抽滤除MgSO 4，将滤液旋蒸，得到粘稠液体，采用硅胶柱分离目标产物。洗脱液为乙酸乙酯和石油醚，体积比为1∶3。将分离出的黄色晶体置于50℃真空烘箱中干燥48h得到纯净BPMA 8.45 g，产率为59%。图1为BPMA的合成路线。 　　4.预辐照接枝 　　将PVDF装入袋中，密封;将该袋放入钴源内，用60Co-y射线辐照，辐照剂星为15 kGy。辐照后低温保存待用。将4.8 g预辐照的PVDF和1.2 gBPMA置于微星混合流变仪中进行反应。温度为190℃，转速50 r/min，时间6min。将反应后粗产物溶解于DMAc中，再用无水乙醇沉淀，离心，重复进行3次后，在索氏提取器中用无水乙醇抽提除去未反应的BPMA。将抽提后产物置于70°℃真空烘箱中干燥48 h，进行表征。 　　5．性能测试与结构表征 　　1H-NMR测试:分别取5 mg BPMA及10 mgPVDF-g-BPMA，用NMR仪进行分析，溶剂为氩代二甲基亚矾。TG分析:空气气氛，升温速率10℃/min，温度范围为30~800℃。FTIR测试:将PVDF及PVDF-g-BPMA溶液涂膜制成厚度为40 um的薄膜进行测试，测试波数范围为500~4 000 cm-1，分辨率2cm-1，全反射模式。DSC测试:将6 mg试样置于氧化铝样品锅中，在氮气氛围下采用二次升温法，以10℃/min升降温速率对接枝前后PVDF进行测试。IC测试:将接枝前后PVDF进行F元素含量测试。WAXD测试:将PVDF及PVDF-g-BPMA溶液涂膜制成薄膜进行测试，Cu靶，测试角度10°~50°。紫外线吸收性能表征:将制得的PVDF及PVDF-g-BPMA薄膜(40 um)进行紫外–可见光(UV-vis)透过率测试，扫描间隔1 nm，扫描范围200~800 nm。耐迁移性能测试:将制备的PVDF/BPMA复合膜及PVDF-g-BPMA膜(厚度40 um)以乙醇为溶剂分别抽提48 h进行紫外线吸收性能测试。
Application of UV Absorber in High Temperature Material 2024-03-02 14:57:35.725
Within 300 degrees, the general UV agent does not need to consider the thermal decomposition. Although there will be a certain degree of heat loss (TGA) at high temperatures, UV agents with relatively small TGA and suitable effects can be selected when used, and the dosage can also be increased to avoid insufficient weight after volatilization. The main feed is enough. If the melting point is low, side feed or masterbatch can be selected. Light stabilizer 770 in the PA6/glass fiber system, the effect is very good.
What is the difference between photosensitizer and ultraviolet absorber? 2024-03-02 14:57:09.926
Photosensitizer, also known as sensitizer, sensitizer. In the photochemical reaction, there is a class of molecules, they only absorb photons and transfer energy to those who can not absorb photons of molecules, promote the chemical reaction, and itself does not participate in the chemical reaction, return to the original state, this kind of molecule is called photosensitizer. Ultraviolet absorber. Because the sun's rays contain a lot of harmful ultraviolet light to colored objects, its wavelength is about 290-460 nanometers, these harmful ultraviolet light through chemical oxidation reduction (Redox reaction), so that the color molecules finally decompose and fade. The use of UV absorbers to effectively prevent, or reduce the damage to the color of, the protected object. Prevent harmful UV light from damaging the color. UV absorbers can be divided into the following categories according to their chemical structures: salicylates, benzophenones, benzotriazoles, substituted acrylonitriles, triazines and hindered amines. Conditions of action of photosensitizers (1) can be first activated by light irradiation; (2) There is a sufficient concentration in the system and a sufficient amount of photons can be absorbed; (3) must be able to transfer their energy to the reactants. Photosensitive reagents are generally aromatic ketones and benzoin ethers: such as benzophenone, benzoin dimethyl ether and so on
What are the special properties of water-based UV absorbers? 2024-03-02 14:56:38.990
The water-based UV absorber is white to light yellow powder, which is made by exquisite process. has the following characteristics: Good water solubility, light yellow high transparent liquid after being dissolved in water; Can improve the stability of various substances in aqueous system; Very high absorption efficiency, absorption wavelength in 290-390nm; Good thermal stability to light, not easy to corruption, long use cycle; Very low use concentration, high absorption performance; Powder packaging, convenient transportation; Non-toxic, no teratogenic side effects, harmless environmental protection The water-based UV absorber is a water-soluble neutral broad-spectrum UV absorber, suitable for absorbing UV wavelengths in the range of 290-390nm. Mainly used in water-based coating system, water-soluble chemical sunscreen, sunscreen, emulsion, shampoo, shower gel, oil water-based drilling fluid, oil water-based lubricants and other organic water-based systems. Can effectively prevent the various hazards caused by ultraviolet rays.