核殼乳液聚合課件

1、核殼乳液聚合,1,核殼乳液聚合,核殼乳液聚合,2,核殼乳液聚合,核殼乳液聚合,3,什么是核殼乳液聚合,種子乳液聚合 所謂種子乳液聚合是先將少量單體按一般乳液聚合法制得種子膠乳(100150nm)。 然后將少量種子膠乳(1%3%)，加入正式乳液聚合的配方中。 種子膠乳粒將被單體所溶脹并吸附水相中產(chǎn)生的自由基而引發(fā)聚合，經(jīng)過(guò)多級(jí)溶脹聚合，使粒子逐漸增大，最終可達(dá)12m或更大。(普通50-200nm) 可用來(lái)制備粒徑較大、分布較窄的乳膠粒子。 在第二步反應(yīng)中，要控制乳化劑的用量，以抑制新的粒子生成,核殼乳液聚合,4,什么是核殼乳液聚合,核殼乳液聚合 核殼乳液聚合是種子乳液聚合的發(fā)展。 若種子聚合和后

2、繼聚合采用不同單體，則形成核殼結(jié)構(gòu)的膠粒，在核與殼的界面上形成接枝層，增加兩者的相容性和粘結(jié)力，提高力學(xué)性能。 在總配比完全相同的情況下，因?yàn)榻M分性質(zhì)的差異，采用種子乳液聚合的方法，控制不同的加料順序和條件，可以得到結(jié)構(gòu)形態(tài)不同的核殼乳膠粒子。 與普通乳液乳液聚合相比，它有顯著的優(yōu)越性，如在流變性、最低成膜溫度、玻璃轉(zhuǎn)化溫度、抗張強(qiáng)度、粘接性能、加工性等方面有顯著的特點(diǎn),核殼乳液聚合,5,什么是核殼乳液聚合,種子乳液聚合,核殼乳液聚合,使粒子長(zhǎng)大,后繼的正式聚合采用同一種單體,少量單體先形成種子膠乳,形成核殼結(jié)構(gòu),后繼聚合采用不同單體,少量單體先形成核結(jié)構(gòu)部分,核殼乳液聚合,6,核殼乳液聚合的

3、核殼結(jié)構(gòu),乳膠粒的核殼結(jié)構(gòu)： 在乳膠粒的中心附近是一個(gè)富聚合物的核，其中聚合物含量大而單體含量少。 在核的外圍是一層富單體的殼;在殼表面上吸附乳化劑分子而成一單分子層，以使該乳膠粒穩(wěn)定的懸浮在水相中。 在核與殼的界面上，分布有正在增長(zhǎng)的或失去活性的聚合物末端，聚合反應(yīng)就是發(fā)生在這個(gè)界面上,核殼乳液聚合,7,核殼乳液聚合的核殼結(jié)構(gòu),單體、乳化劑分別處在水溶液、膠束、液滴三相中的示意圖,核殼乳液聚合,8,影響核殼乳液聚合的因素,根據(jù)核和殼單體的不同，正常的核殼聚合物基本上有兩種類型： 硬核軟殼型：這類聚合物主要用作涂料。 軟核硬殼型：調(diào)節(jié)玻璃化溫度或最低成膜溫度。以丁二烯丙烯酸丁酯等軟單體，經(jīng)乳液

4、聚合后為種子，甲基丙烯酸甲酯苯乙烯丙烯睛等為硬單體，后來(lái)加入繼續(xù)聚合，就成為硬殼層。以B（聚丁二烯）為核，S（苯乙烯）和A（丙烯氰）共聚物為殼，就成了著名的ABS工程塑料,核殼乳液聚合,9,影響核殼乳液聚合的因素,核殼乳液粒子構(gòu)成機(jī)理 接枝機(jī)理 一種單體在另一種聚合物存在下進(jìn)行聚合時(shí)，在適當(dāng)?shù)臈l件下，會(huì)多去聚合物上的活潑氫原子而發(fā)生接枝共聚。如St-BA核殼乳液聚合 互穿聚合物網(wǎng)絡(luò)機(jī)理 兩種聚合物分子鏈相互貫穿并以化學(xué)鍵的方式各自交聯(lián)而成的網(wǎng)絡(luò)結(jié)構(gòu) 離子鍵合機(jī)理不同電荷的相互作用,核殼乳液聚合,10,影響核殼乳液聚合的因素,溶脹法：先不補(bǔ)加引發(fā)劑，而加入殼單體，使殼單體溶脹進(jìn)入乳膠內(nèi)。這種方法

5、不僅種子乳膠粒表面的單體濃度很高，而且殼單體有充分時(shí)間滲入到種子乳膠粒子內(nèi)部,間歇法：殼單體一次性加入，在引發(fā)劑存在下引發(fā)聚合，這種方法也使乳膠粒表面單體濃度很高,半連續(xù)法：將殼單體連續(xù)滴加，使種子乳膠的表面和內(nèi)部殼單體濃度都很低，既聚合物處在饑渴狀態(tài).此只能在核聚合物上連續(xù)形成殼層而缺乏核殼層間的結(jié)合,核殼乳液聚合,11,影響核殼乳液聚合的因素,影響核殼結(jié)構(gòu)的因素除了兩中單體的加料次序外，還與單體的親水性有關(guān)。 一般乳液聚合都以水為分散介質(zhì)，親水性較大的聚合物易和介質(zhì)水接近，而疏水性傾向于排斥介質(zhì)水，因而形成不同結(jié)構(gòu)形態(tài)的膠乳粒子。 正常結(jié)構(gòu)和非正常的結(jié)構(gòu)形態(tài)(如翻轉(zhuǎn)形等)乳膠粒,核殼乳液聚

6、合,12,核殼乳液聚合的應(yīng)用舉例（1,多層特種結(jié)構(gòu)聚合物乳膠粒子 遞變進(jìn)料、單體A單體B、洋蔥 當(dāng)R0：R1=1：2，內(nèi)部富含B外部富含A的核殼聚合物； 當(dāng)R0R1，無(wú)規(guī)共聚物；當(dāng)R0R1，典型的B核A殼聚合物,13,核殼乳液聚合的應(yīng)用舉例（2,synthesis and application of anionic acrylic（陰離子丙烯酸） emulsion used as paper wet-strength additive,核殼乳液聚合,Related imformation,Title synthesis and application of anionic acrylic e

7、mulsion（陰離子丙烯酸） used as paper wet-strength additive Authors Xin Liu, Chunhua Tian, Yuying Wu, Xueming Zhang College of Materials Science and Technology, Beijing Forestry University From 4th International Conference on Pulping, Papermaking and Biotechnology,核殼乳液聚合,Contents,1. Abstract,2. Introduction

8、,3. Experienment,4. Results and discussion,5. Conclusion,核殼乳液聚合,Abstract,polymerization butyl acrylate (BA) as soft monomer, styrene (St) as hard monomer sodium dodecyl sulfate (SDS) and dodecyl polyoxy ethylene (OP-10) as emulsifiers under nitrogen 丙烯酸丁酯、苯乙烯、十二烷基硫酸鈉、烷基酚聚氧乙烯醚 the optimal conditions

9、the ratio of SDS to OP-10 was 1:2, total dosage was 8%; the dosage of initiator was 0.25 g, including 0.15g in seeded polymerization process and 0.1g in shell polymerization process; the functional monomer dosage was 7.5 g,核殼乳液聚合,Abstract,used as wet strength agent single use of APSBM（苯乙烯-丙烯酸丁酯-甲基丙烯

10、酸） was not good simultaneous use of 0.3% APSBM and 0.7% PAE showed great improvement of wet strength to 38% SEM photographs showed that the appearance of paper treated with 0.7% PAE and 0.3% APSBM had a close crosslinking（交聯(lián),核殼乳液聚合,Introduction,background 1/environmental-friendly products-MF（脲- 甲醛樹(shù)脂

11、）/UF（三聚氰胺一甲醛樹(shù)脂）/PAE（聚酰胺環(huán)氧氯丙烷） 2/excellent penetrability（滲透性）, affinity（親和力）, and film forming ability;it can disperse in water without organic solvent 3/some disadvantages: high temperature of film forming, lower rigidity（剛度）, tending to get soft, poor water resistance（抗水性） of cured（熟化） film, ect 4/

12、One solution to solve above mentioned problemsis to develop special structure of particles called core-shell structure （核殼結(jié)構(gòu)）of the polymer particles,核殼乳液聚合,Introduction,idea a new concept of particle design, that is, changing the structure of latex（膠乳） particles through designing the composition of

13、 core and shell structures of latex particles as to improve the properties of emulsion acrylate copolymer（丙烯酸共聚物） emulsion with core-shell structure was prepared using styrene (St) （苯乙烯）as hard monomer and butyl acrylate (BA) （丙烯酸丁酯）as soft monomer,核殼乳液聚合,Experienment,A constitutional formula synthe

14、sized by St（苯乙烯）,BA（丙烯酸丁酯） and -MAA（甲基丙烯酸,核殼乳液聚合,Experienment,Copolymer synthesis Seed（種子聚合） emulsifier, buffer and distilled water mixed seed monomers, potassium peroxydisulfate（過(guò)硫酸鉀） Core （核聚合） core monomers which were well pre-emulsified Shell（殼聚合） well pre-emulsified shell monomers,核殼乳液聚合,Experi

15、enment,Paper sheets preparation and analysis hardwood bleached kraft pulp(HBKP)（闊葉木漂白硫酸鹽漿） 80 g/m2 basis weight Wet tensile strength and folding endurance Emulsion characterization observation of emulsions state,viscosity and color; the solid content, conversion mechanical stability, ionic stability

16、, pH stability and storing stability (one month,23,Thank You,核殼乳液聚合,Results and discussion,1/more than 98% 2/as the amount of SDS increased, the flocculation of emulsion significantly increased and the storing stability reduced,also the emulsion began to layer. 3/same charge causes the bonding of th

17、e emulsifier molecules and latex particles to decline,核殼乳液聚合,Results and discussion,During seed reaction stage, when emulsifier dosage was 3%, the monomer conversion rate was the lowestof all; During core reaction stage, as the reaction went on, the monomer conversion rate increased fast,especially

18、the emulsifier dosage 3% increased significantly; During shell reaction stage, the conversion rate increased slowly; At the end of reaction, the conversion rates of four different emulsifier dosages system were almost the same, which could all reach more than 99,核殼乳液聚合,Results and discussion,1/As the amount of emulsifier increased, the reaction began to gel and the blue fluorescence became less obvious,核殼乳液聚合,Results and discussion,1/ 0.00/90.49% 0.10/98.87% 0.15/98.56% 2/it need additional initiator during shell polymerization reaction,because of the cons